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| author | thegeorg <[email protected]> | 2024-03-15 23:28:02 +0300 |
|---|---|---|
| committer | thegeorg <[email protected]> | 2024-03-15 23:38:24 +0300 |
| commit | 6635e51dd2fc4c8fbc3e510cd31c9c9102b7cfda (patch) | |
| tree | d51d048d3eb5d7a24ec6e4302b589513a3b97de3 /contrib/tools/python/src/Lib/pydoc_data/topics.py | |
| parent | e894914751eea93bb23102a533c8d481b80c2560 (diff) | |
Store generated list of frozen modules for contrib/tools/python
a94357bf8071b16879eeabac1f52f54e278c03ed
Diffstat (limited to 'contrib/tools/python/src/Lib/pydoc_data/topics.py')
| -rw-r--r-- | contrib/tools/python/src/Lib/pydoc_data/topics.py | 13578 |
1 files changed, 0 insertions, 13578 deletions
diff --git a/contrib/tools/python/src/Lib/pydoc_data/topics.py b/contrib/tools/python/src/Lib/pydoc_data/topics.py deleted file mode 100644 index 5fc84a8ddbe..00000000000 --- a/contrib/tools/python/src/Lib/pydoc_data/topics.py +++ /dev/null @@ -1,13578 +0,0 @@ -# -*- coding: utf-8 -*- -# Autogenerated by Sphinx on Sat Aug 26 11:16:28 2017 -topics = {'assert': '\n' - 'The "assert" statement\n' - '**********************\n' - '\n' - 'Assert statements are a convenient way to insert debugging ' - 'assertions\n' - 'into a program:\n' - '\n' - ' assert_stmt ::= "assert" expression ["," expression]\n' - '\n' - 'The simple form, "assert expression", is equivalent to\n' - '\n' - ' if __debug__:\n' - ' if not expression: raise AssertionError\n' - '\n' - 'The extended form, "assert expression1, expression2", is ' - 'equivalent to\n' - '\n' - ' if __debug__:\n' - ' if not expression1: raise AssertionError(expression2)\n' - '\n' - 'These equivalences assume that "__debug__" and "AssertionError" ' - 'refer\n' - 'to the built-in variables with those names. In the current\n' - 'implementation, the built-in variable "__debug__" is "True" under\n' - 'normal circumstances, "False" when optimization is requested ' - '(command\n' - 'line option -O). The current code generator emits no code for an\n' - 'assert statement when optimization is requested at compile time. ' - 'Note\n' - 'that it is unnecessary to include the source code for the ' - 'expression\n' - 'that failed in the error message; it will be displayed as part of ' - 'the\n' - 'stack trace.\n' - '\n' - 'Assignments to "__debug__" are illegal. The value for the ' - 'built-in\n' - 'variable is determined when the interpreter starts.\n', - 'assignment': '\n' - 'Assignment statements\n' - '*********************\n' - '\n' - 'Assignment statements are used to (re)bind names to values and ' - 'to\n' - 'modify attributes or items of mutable objects:\n' - '\n' - ' assignment_stmt ::= (target_list "=")+ (expression_list | ' - 'yield_expression)\n' - ' target_list ::= target ("," target)* [","]\n' - ' target ::= identifier\n' - ' | "(" target_list ")"\n' - ' | "[" [target_list] "]"\n' - ' | attributeref\n' - ' | subscription\n' - ' | slicing\n' - '\n' - '(See section Primaries for the syntax definitions for the last ' - 'three\n' - 'symbols.)\n' - '\n' - 'An assignment statement evaluates the expression list ' - '(remember that\n' - 'this can be a single expression or a comma-separated list, the ' - 'latter\n' - 'yielding a tuple) and assigns the single resulting object to ' - 'each of\n' - 'the target lists, from left to right.\n' - '\n' - 'Assignment is defined recursively depending on the form of the ' - 'target\n' - '(list). When a target is part of a mutable object (an ' - 'attribute\n' - 'reference, subscription or slicing), the mutable object must\n' - 'ultimately perform the assignment and decide about its ' - 'validity, and\n' - 'may raise an exception if the assignment is unacceptable. The ' - 'rules\n' - 'observed by various types and the exceptions raised are given ' - 'with the\n' - 'definition of the object types (see section The standard type\n' - 'hierarchy).\n' - '\n' - 'Assignment of an object to a target list is recursively ' - 'defined as\n' - 'follows.\n' - '\n' - '* If the target list is a single target: The object is ' - 'assigned to\n' - ' that target.\n' - '\n' - '* If the target list is a comma-separated list of targets: ' - 'The\n' - ' object must be an iterable with the same number of items as ' - 'there\n' - ' are targets in the target list, and the items are assigned, ' - 'from\n' - ' left to right, to the corresponding targets.\n' - '\n' - 'Assignment of an object to a single target is recursively ' - 'defined as\n' - 'follows.\n' - '\n' - '* If the target is an identifier (name):\n' - '\n' - ' * If the name does not occur in a "global" statement in the\n' - ' current code block: the name is bound to the object in the ' - 'current\n' - ' local namespace.\n' - '\n' - ' * Otherwise: the name is bound to the object in the current ' - 'global\n' - ' namespace.\n' - '\n' - ' The name is rebound if it was already bound. This may cause ' - 'the\n' - ' reference count for the object previously bound to the name ' - 'to reach\n' - ' zero, causing the object to be deallocated and its ' - 'destructor (if it\n' - ' has one) to be called.\n' - '\n' - '* If the target is a target list enclosed in parentheses or ' - 'in\n' - ' square brackets: The object must be an iterable with the ' - 'same number\n' - ' of items as there are targets in the target list, and its ' - 'items are\n' - ' assigned, from left to right, to the corresponding targets.\n' - '\n' - '* If the target is an attribute reference: The primary ' - 'expression in\n' - ' the reference is evaluated. It should yield an object with\n' - ' assignable attributes; if this is not the case, "TypeError" ' - 'is\n' - ' raised. That object is then asked to assign the assigned ' - 'object to\n' - ' the given attribute; if it cannot perform the assignment, it ' - 'raises\n' - ' an exception (usually but not necessarily ' - '"AttributeError").\n' - '\n' - ' Note: If the object is a class instance and the attribute ' - 'reference\n' - ' occurs on both sides of the assignment operator, the RHS ' - 'expression,\n' - ' "a.x" can access either an instance attribute or (if no ' - 'instance\n' - ' attribute exists) a class attribute. The LHS target "a.x" ' - 'is always\n' - ' set as an instance attribute, creating it if necessary. ' - 'Thus, the\n' - ' two occurrences of "a.x" do not necessarily refer to the ' - 'same\n' - ' attribute: if the RHS expression refers to a class ' - 'attribute, the\n' - ' LHS creates a new instance attribute as the target of the\n' - ' assignment:\n' - '\n' - ' class Cls:\n' - ' x = 3 # class variable\n' - ' inst = Cls()\n' - ' inst.x = inst.x + 1 # writes inst.x as 4 leaving Cls.x ' - 'as 3\n' - '\n' - ' This description does not necessarily apply to descriptor\n' - ' attributes, such as properties created with "property()".\n' - '\n' - '* If the target is a subscription: The primary expression in ' - 'the\n' - ' reference is evaluated. It should yield either a mutable ' - 'sequence\n' - ' object (such as a list) or a mapping object (such as a ' - 'dictionary).\n' - ' Next, the subscript expression is evaluated.\n' - '\n' - ' If the primary is a mutable sequence object (such as a ' - 'list), the\n' - ' subscript must yield a plain integer. If it is negative, ' - 'the\n' - " sequence's length is added to it. The resulting value must " - 'be a\n' - " nonnegative integer less than the sequence's length, and " - 'the\n' - ' sequence is asked to assign the assigned object to its item ' - 'with\n' - ' that index. If the index is out of range, "IndexError" is ' - 'raised\n' - ' (assignment to a subscripted sequence cannot add new items ' - 'to a\n' - ' list).\n' - '\n' - ' If the primary is a mapping object (such as a dictionary), ' - 'the\n' - " subscript must have a type compatible with the mapping's key " - 'type,\n' - ' and the mapping is then asked to create a key/datum pair ' - 'which maps\n' - ' the subscript to the assigned object. This can either ' - 'replace an\n' - ' existing key/value pair with the same key value, or insert a ' - 'new\n' - ' key/value pair (if no key with the same value existed).\n' - '\n' - '* If the target is a slicing: The primary expression in the\n' - ' reference is evaluated. It should yield a mutable sequence ' - 'object\n' - ' (such as a list). The assigned object should be a sequence ' - 'object\n' - ' of the same type. Next, the lower and upper bound ' - 'expressions are\n' - ' evaluated, insofar they are present; defaults are zero and ' - 'the\n' - " sequence's length. The bounds should evaluate to (small) " - 'integers.\n' - " If either bound is negative, the sequence's length is added " - 'to it.\n' - ' The resulting bounds are clipped to lie between zero and ' - 'the\n' - " sequence's length, inclusive. Finally, the sequence object " - 'is asked\n' - ' to replace the slice with the items of the assigned ' - 'sequence. The\n' - ' length of the slice may be different from the length of the ' - 'assigned\n' - ' sequence, thus changing the length of the target sequence, ' - 'if the\n' - ' object allows it.\n' - '\n' - '**CPython implementation detail:** In the current ' - 'implementation, the\n' - 'syntax for targets is taken to be the same as for expressions, ' - 'and\n' - 'invalid syntax is rejected during the code generation phase, ' - 'causing\n' - 'less detailed error messages.\n' - '\n' - 'WARNING: Although the definition of assignment implies that ' - 'overlaps\n' - "between the left-hand side and the right-hand side are 'safe' " - '(for\n' - 'example "a, b = b, a" swaps two variables), overlaps *within* ' - 'the\n' - 'collection of assigned-to variables are not safe! For ' - 'instance, the\n' - 'following program prints "[0, 2]":\n' - '\n' - ' x = [0, 1]\n' - ' i = 0\n' - ' i, x[i] = 1, 2\n' - ' print x\n' - '\n' - '\n' - 'Augmented assignment statements\n' - '===============================\n' - '\n' - 'Augmented assignment is the combination, in a single ' - 'statement, of a\n' - 'binary operation and an assignment statement:\n' - '\n' - ' augmented_assignment_stmt ::= augtarget augop ' - '(expression_list | yield_expression)\n' - ' augtarget ::= identifier | attributeref | ' - 'subscription | slicing\n' - ' augop ::= "+=" | "-=" | "*=" | "/=" | ' - '"//=" | "%=" | "**="\n' - ' | ">>=" | "<<=" | "&=" | "^=" | "|="\n' - '\n' - '(See section Primaries for the syntax definitions for the last ' - 'three\n' - 'symbols.)\n' - '\n' - 'An augmented assignment evaluates the target (which, unlike ' - 'normal\n' - 'assignment statements, cannot be an unpacking) and the ' - 'expression\n' - 'list, performs the binary operation specific to the type of ' - 'assignment\n' - 'on the two operands, and assigns the result to the original ' - 'target.\n' - 'The target is only evaluated once.\n' - '\n' - 'An augmented assignment expression like "x += 1" can be ' - 'rewritten as\n' - '"x = x + 1" to achieve a similar, but not exactly equal ' - 'effect. In the\n' - 'augmented version, "x" is only evaluated once. Also, when ' - 'possible,\n' - 'the actual operation is performed *in-place*, meaning that ' - 'rather than\n' - 'creating a new object and assigning that to the target, the ' - 'old object\n' - 'is modified instead.\n' - '\n' - 'With the exception of assigning to tuples and multiple targets ' - 'in a\n' - 'single statement, the assignment done by augmented assignment\n' - 'statements is handled the same way as normal assignments. ' - 'Similarly,\n' - 'with the exception of the possible *in-place* behavior, the ' - 'binary\n' - 'operation performed by augmented assignment is the same as the ' - 'normal\n' - 'binary operations.\n' - '\n' - 'For targets which are attribute references, the same caveat ' - 'about\n' - 'class and instance attributes applies as for regular ' - 'assignments.\n', - 'atom-identifiers': '\n' - 'Identifiers (Names)\n' - '*******************\n' - '\n' - 'An identifier occurring as an atom is a name. See ' - 'section Identifiers\n' - 'and keywords for lexical definition and section Naming ' - 'and binding for\n' - 'documentation of naming and binding.\n' - '\n' - 'When the name is bound to an object, evaluation of the ' - 'atom yields\n' - 'that object. When a name is not bound, an attempt to ' - 'evaluate it\n' - 'raises a "NameError" exception.\n' - '\n' - '**Private name mangling:** When an identifier that ' - 'textually occurs in\n' - 'a class definition begins with two or more underscore ' - 'characters and\n' - 'does not end in two or more underscores, it is ' - 'considered a *private\n' - 'name* of that class. Private names are transformed to a ' - 'longer form\n' - 'before code is generated for them. The transformation ' - 'inserts the\n' - 'class name, with leading underscores removed and a ' - 'single underscore\n' - 'inserted, in front of the name. For example, the ' - 'identifier "__spam"\n' - 'occurring in a class named "Ham" will be transformed to ' - '"_Ham__spam".\n' - 'This transformation is independent of the syntactical ' - 'context in which\n' - 'the identifier is used. If the transformed name is ' - 'extremely long\n' - '(longer than 255 characters), implementation defined ' - 'truncation may\n' - 'happen. If the class name consists only of underscores, ' - 'no\n' - 'transformation is done.\n', - 'atom-literals': '\n' - 'Literals\n' - '********\n' - '\n' - 'Python supports string literals and various numeric ' - 'literals:\n' - '\n' - ' literal ::= stringliteral | integer | longinteger\n' - ' | floatnumber | imagnumber\n' - '\n' - 'Evaluation of a literal yields an object of the given type ' - '(string,\n' - 'integer, long integer, floating point number, complex ' - 'number) with the\n' - 'given value. The value may be approximated in the case of ' - 'floating\n' - 'point and imaginary (complex) literals. See section ' - 'Literals for\n' - 'details.\n' - '\n' - 'All literals correspond to immutable data types, and hence ' - 'the\n' - "object's identity is less important than its value. " - 'Multiple\n' - 'evaluations of literals with the same value (either the ' - 'same\n' - 'occurrence in the program text or a different occurrence) ' - 'may obtain\n' - 'the same object or a different object with the same ' - 'value.\n', - 'attribute-access': '\n' - 'Customizing attribute access\n' - '****************************\n' - '\n' - 'The following methods can be defined to customize the ' - 'meaning of\n' - 'attribute access (use of, assignment to, or deletion of ' - '"x.name") for\n' - 'class instances.\n' - '\n' - 'object.__getattr__(self, name)\n' - '\n' - ' Called when an attribute lookup has not found the ' - 'attribute in the\n' - ' usual places (i.e. it is not an instance attribute ' - 'nor is it found\n' - ' in the class tree for "self"). "name" is the ' - 'attribute name. This\n' - ' method should return the (computed) attribute value ' - 'or raise an\n' - ' "AttributeError" exception.\n' - '\n' - ' Note that if the attribute is found through the ' - 'normal mechanism,\n' - ' "__getattr__()" is not called. (This is an ' - 'intentional asymmetry\n' - ' between "__getattr__()" and "__setattr__()".) This is ' - 'done both for\n' - ' efficiency reasons and because otherwise ' - '"__getattr__()" would have\n' - ' no way to access other attributes of the instance. ' - 'Note that at\n' - ' least for instance variables, you can fake total ' - 'control by not\n' - ' inserting any values in the instance attribute ' - 'dictionary (but\n' - ' instead inserting them in another object). See the\n' - ' "__getattribute__()" method below for a way to ' - 'actually get total\n' - ' control in new-style classes.\n' - '\n' - 'object.__setattr__(self, name, value)\n' - '\n' - ' Called when an attribute assignment is attempted. ' - 'This is called\n' - ' instead of the normal mechanism (i.e. store the value ' - 'in the\n' - ' instance dictionary). *name* is the attribute name, ' - '*value* is the\n' - ' value to be assigned to it.\n' - '\n' - ' If "__setattr__()" wants to assign to an instance ' - 'attribute, it\n' - ' should not simply execute "self.name = value" --- ' - 'this would cause\n' - ' a recursive call to itself. Instead, it should ' - 'insert the value in\n' - ' the dictionary of instance attributes, e.g., ' - '"self.__dict__[name] =\n' - ' value". For new-style classes, rather than accessing ' - 'the instance\n' - ' dictionary, it should call the base class method with ' - 'the same\n' - ' name, for example, "object.__setattr__(self, name, ' - 'value)".\n' - '\n' - 'object.__delattr__(self, name)\n' - '\n' - ' Like "__setattr__()" but for attribute deletion ' - 'instead of\n' - ' assignment. This should only be implemented if "del ' - 'obj.name" is\n' - ' meaningful for the object.\n' - '\n' - '\n' - 'More attribute access for new-style classes\n' - '===========================================\n' - '\n' - 'The following methods only apply to new-style classes.\n' - '\n' - 'object.__getattribute__(self, name)\n' - '\n' - ' Called unconditionally to implement attribute ' - 'accesses for\n' - ' instances of the class. If the class also defines ' - '"__getattr__()",\n' - ' the latter will not be called unless ' - '"__getattribute__()" either\n' - ' calls it explicitly or raises an "AttributeError". ' - 'This method\n' - ' should return the (computed) attribute value or raise ' - 'an\n' - ' "AttributeError" exception. In order to avoid ' - 'infinite recursion in\n' - ' this method, its implementation should always call ' - 'the base class\n' - ' method with the same name to access any attributes it ' - 'needs, for\n' - ' example, "object.__getattribute__(self, name)".\n' - '\n' - ' Note: This method may still be bypassed when looking ' - 'up special\n' - ' methods as the result of implicit invocation via ' - 'language syntax\n' - ' or built-in functions. See Special method lookup ' - 'for new-style\n' - ' classes.\n' - '\n' - '\n' - 'Implementing Descriptors\n' - '========================\n' - '\n' - 'The following methods only apply when an instance of the ' - 'class\n' - 'containing the method (a so-called *descriptor* class) ' - 'appears in an\n' - '*owner* class (the descriptor must be in either the ' - "owner's class\n" - 'dictionary or in the class dictionary for one of its ' - 'parents). In the\n' - 'examples below, "the attribute" refers to the attribute ' - 'whose name is\n' - "the key of the property in the owner class' " - '"__dict__".\n' - '\n' - 'object.__get__(self, instance, owner)\n' - '\n' - ' Called to get the attribute of the owner class (class ' - 'attribute\n' - ' access) or of an instance of that class (instance ' - 'attribute\n' - ' access). *owner* is always the owner class, while ' - '*instance* is the\n' - ' instance that the attribute was accessed through, or ' - '"None" when\n' - ' the attribute is accessed through the *owner*. This ' - 'method should\n' - ' return the (computed) attribute value or raise an ' - '"AttributeError"\n' - ' exception.\n' - '\n' - 'object.__set__(self, instance, value)\n' - '\n' - ' Called to set the attribute on an instance *instance* ' - 'of the owner\n' - ' class to a new value, *value*.\n' - '\n' - 'object.__delete__(self, instance)\n' - '\n' - ' Called to delete the attribute on an instance ' - '*instance* of the\n' - ' owner class.\n' - '\n' - '\n' - 'Invoking Descriptors\n' - '====================\n' - '\n' - 'In general, a descriptor is an object attribute with ' - '"binding\n' - 'behavior", one whose attribute access has been ' - 'overridden by methods\n' - 'in the descriptor protocol: "__get__()", "__set__()", ' - 'and\n' - '"__delete__()". If any of those methods are defined for ' - 'an object, it\n' - 'is said to be a descriptor.\n' - '\n' - 'The default behavior for attribute access is to get, ' - 'set, or delete\n' - "the attribute from an object's dictionary. For instance, " - '"a.x" has a\n' - 'lookup chain starting with "a.__dict__[\'x\']", then\n' - '"type(a).__dict__[\'x\']", and continuing through the ' - 'base classes of\n' - '"type(a)" excluding metaclasses.\n' - '\n' - 'However, if the looked-up value is an object defining ' - 'one of the\n' - 'descriptor methods, then Python may override the default ' - 'behavior and\n' - 'invoke the descriptor method instead. Where this occurs ' - 'in the\n' - 'precedence chain depends on which descriptor methods ' - 'were defined and\n' - 'how they were called. Note that descriptors are only ' - 'invoked for new\n' - 'style objects or classes (ones that subclass "object()" ' - 'or "type()").\n' - '\n' - 'The starting point for descriptor invocation is a ' - 'binding, "a.x". How\n' - 'the arguments are assembled depends on "a":\n' - '\n' - 'Direct Call\n' - ' The simplest and least common call is when user code ' - 'directly\n' - ' invokes a descriptor method: "x.__get__(a)".\n' - '\n' - 'Instance Binding\n' - ' If binding to a new-style object instance, "a.x" is ' - 'transformed\n' - ' into the call: "type(a).__dict__[\'x\'].__get__(a, ' - 'type(a))".\n' - '\n' - 'Class Binding\n' - ' If binding to a new-style class, "A.x" is transformed ' - 'into the\n' - ' call: "A.__dict__[\'x\'].__get__(None, A)".\n' - '\n' - 'Super Binding\n' - ' If "a" is an instance of "super", then the binding ' - '"super(B,\n' - ' obj).m()" searches "obj.__class__.__mro__" for the ' - 'base class "A"\n' - ' immediately preceding "B" and then invokes the ' - 'descriptor with the\n' - ' call: "A.__dict__[\'m\'].__get__(obj, ' - 'obj.__class__)".\n' - '\n' - 'For instance bindings, the precedence of descriptor ' - 'invocation depends\n' - 'on the which descriptor methods are defined. A ' - 'descriptor can define\n' - 'any combination of "__get__()", "__set__()" and ' - '"__delete__()". If it\n' - 'does not define "__get__()", then accessing the ' - 'attribute will return\n' - 'the descriptor object itself unless there is a value in ' - "the object's\n" - 'instance dictionary. If the descriptor defines ' - '"__set__()" and/or\n' - '"__delete__()", it is a data descriptor; if it defines ' - 'neither, it is\n' - 'a non-data descriptor. Normally, data descriptors ' - 'define both\n' - '"__get__()" and "__set__()", while non-data descriptors ' - 'have just the\n' - '"__get__()" method. Data descriptors with "__set__()" ' - 'and "__get__()"\n' - 'defined always override a redefinition in an instance ' - 'dictionary. In\n' - 'contrast, non-data descriptors can be overridden by ' - 'instances.\n' - '\n' - 'Python methods (including "staticmethod()" and ' - '"classmethod()") are\n' - 'implemented as non-data descriptors. Accordingly, ' - 'instances can\n' - 'redefine and override methods. This allows individual ' - 'instances to\n' - 'acquire behaviors that differ from other instances of ' - 'the same class.\n' - '\n' - 'The "property()" function is implemented as a data ' - 'descriptor.\n' - 'Accordingly, instances cannot override the behavior of a ' - 'property.\n' - '\n' - '\n' - '__slots__\n' - '=========\n' - '\n' - 'By default, instances of both old and new-style classes ' - 'have a\n' - 'dictionary for attribute storage. This wastes space for ' - 'objects\n' - 'having very few instance variables. The space ' - 'consumption can become\n' - 'acute when creating large numbers of instances.\n' - '\n' - 'The default can be overridden by defining *__slots__* in ' - 'a new-style\n' - 'class definition. The *__slots__* declaration takes a ' - 'sequence of\n' - 'instance variables and reserves just enough space in ' - 'each instance to\n' - 'hold a value for each variable. Space is saved because ' - '*__dict__* is\n' - 'not created for each instance.\n' - '\n' - '__slots__\n' - '\n' - ' This class variable can be assigned a string, ' - 'iterable, or sequence\n' - ' of strings with variable names used by instances. If ' - 'defined in a\n' - ' new-style class, *__slots__* reserves space for the ' - 'declared\n' - ' variables and prevents the automatic creation of ' - '*__dict__* and\n' - ' *__weakref__* for each instance.\n' - '\n' - ' New in version 2.2.\n' - '\n' - 'Notes on using *__slots__*\n' - '\n' - '* When inheriting from a class without *__slots__*, the ' - '*__dict__*\n' - ' attribute of that class will always be accessible, so ' - 'a *__slots__*\n' - ' definition in the subclass is meaningless.\n' - '\n' - '* Without a *__dict__* variable, instances cannot be ' - 'assigned new\n' - ' variables not listed in the *__slots__* definition. ' - 'Attempts to\n' - ' assign to an unlisted variable name raises ' - '"AttributeError". If\n' - ' dynamic assignment of new variables is desired, then ' - 'add\n' - ' "\'__dict__\'" to the sequence of strings in the ' - '*__slots__*\n' - ' declaration.\n' - '\n' - ' Changed in version 2.3: Previously, adding ' - '"\'__dict__\'" to the\n' - ' *__slots__* declaration would not enable the ' - 'assignment of new\n' - ' attributes not specifically listed in the sequence of ' - 'instance\n' - ' variable names.\n' - '\n' - '* Without a *__weakref__* variable for each instance, ' - 'classes\n' - ' defining *__slots__* do not support weak references to ' - 'its\n' - ' instances. If weak reference support is needed, then ' - 'add\n' - ' "\'__weakref__\'" to the sequence of strings in the ' - '*__slots__*\n' - ' declaration.\n' - '\n' - ' Changed in version 2.3: Previously, adding ' - '"\'__weakref__\'" to the\n' - ' *__slots__* declaration would not enable support for ' - 'weak\n' - ' references.\n' - '\n' - '* *__slots__* are implemented at the class level by ' - 'creating\n' - ' descriptors (Implementing Descriptors) for each ' - 'variable name. As a\n' - ' result, class attributes cannot be used to set default ' - 'values for\n' - ' instance variables defined by *__slots__*; otherwise, ' - 'the class\n' - ' attribute would overwrite the descriptor assignment.\n' - '\n' - '* The action of a *__slots__* declaration is limited to ' - 'the class\n' - ' where it is defined. As a result, subclasses will ' - 'have a *__dict__*\n' - ' unless they also define *__slots__* (which must only ' - 'contain names\n' - ' of any *additional* slots).\n' - '\n' - '* If a class defines a slot also defined in a base ' - 'class, the\n' - ' instance variable defined by the base class slot is ' - 'inaccessible\n' - ' (except by retrieving its descriptor directly from the ' - 'base class).\n' - ' This renders the meaning of the program undefined. In ' - 'the future, a\n' - ' check may be added to prevent this.\n' - '\n' - '* Nonempty *__slots__* does not work for classes derived ' - 'from\n' - ' "variable-length" built-in types such as "long", "str" ' - 'and "tuple".\n' - '\n' - '* Any non-string iterable may be assigned to ' - '*__slots__*. Mappings\n' - ' may also be used; however, in the future, special ' - 'meaning may be\n' - ' assigned to the values corresponding to each key.\n' - '\n' - '* *__class__* assignment works only if both classes have ' - 'the same\n' - ' *__slots__*.\n' - '\n' - ' Changed in version 2.6: Previously, *__class__* ' - 'assignment raised an\n' - ' error if either new or old class had *__slots__*.\n', - 'attribute-references': '\n' - 'Attribute references\n' - '********************\n' - '\n' - 'An attribute reference is a primary followed by a ' - 'period and a name:\n' - '\n' - ' attributeref ::= primary "." identifier\n' - '\n' - 'The primary must evaluate to an object of a type ' - 'that supports\n' - 'attribute references, e.g., a module, list, or an ' - 'instance. This\n' - 'object is then asked to produce the attribute whose ' - 'name is the\n' - 'identifier. If this attribute is not available, the ' - 'exception\n' - '"AttributeError" is raised. Otherwise, the type and ' - 'value of the\n' - 'object produced is determined by the object. ' - 'Multiple evaluations of\n' - 'the same attribute reference may yield different ' - 'objects.\n', - 'augassign': '\n' - 'Augmented assignment statements\n' - '*******************************\n' - '\n' - 'Augmented assignment is the combination, in a single statement, ' - 'of a\n' - 'binary operation and an assignment statement:\n' - '\n' - ' augmented_assignment_stmt ::= augtarget augop ' - '(expression_list | yield_expression)\n' - ' augtarget ::= identifier | attributeref | ' - 'subscription | slicing\n' - ' augop ::= "+=" | "-=" | "*=" | "/=" | ' - '"//=" | "%=" | "**="\n' - ' | ">>=" | "<<=" | "&=" | "^=" | "|="\n' - '\n' - '(See section Primaries for the syntax definitions for the last ' - 'three\n' - 'symbols.)\n' - '\n' - 'An augmented assignment evaluates the target (which, unlike ' - 'normal\n' - 'assignment statements, cannot be an unpacking) and the ' - 'expression\n' - 'list, performs the binary operation specific to the type of ' - 'assignment\n' - 'on the two operands, and assigns the result to the original ' - 'target.\n' - 'The target is only evaluated once.\n' - '\n' - 'An augmented assignment expression like "x += 1" can be ' - 'rewritten as\n' - '"x = x + 1" to achieve a similar, but not exactly equal effect. ' - 'In the\n' - 'augmented version, "x" is only evaluated once. Also, when ' - 'possible,\n' - 'the actual operation is performed *in-place*, meaning that ' - 'rather than\n' - 'creating a new object and assigning that to the target, the old ' - 'object\n' - 'is modified instead.\n' - '\n' - 'With the exception of assigning to tuples and multiple targets ' - 'in a\n' - 'single statement, the assignment done by augmented assignment\n' - 'statements is handled the same way as normal assignments. ' - 'Similarly,\n' - 'with the exception of the possible *in-place* behavior, the ' - 'binary\n' - 'operation performed by augmented assignment is the same as the ' - 'normal\n' - 'binary operations.\n' - '\n' - 'For targets which are attribute references, the same caveat ' - 'about\n' - 'class and instance attributes applies as for regular ' - 'assignments.\n', - 'binary': '\n' - 'Binary arithmetic operations\n' - '****************************\n' - '\n' - 'The binary arithmetic operations have the conventional priority\n' - 'levels. Note that some of these operations also apply to certain ' - 'non-\n' - 'numeric types. Apart from the power operator, there are only two\n' - 'levels, one for multiplicative operators and one for additive\n' - 'operators:\n' - '\n' - ' m_expr ::= u_expr | m_expr "*" u_expr | m_expr "//" u_expr | ' - 'm_expr "/" u_expr\n' - ' | m_expr "%" u_expr\n' - ' a_expr ::= m_expr | a_expr "+" m_expr | a_expr "-" m_expr\n' - '\n' - 'The "*" (multiplication) operator yields the product of its ' - 'arguments.\n' - 'The arguments must either both be numbers, or one argument must be ' - 'an\n' - 'integer (plain or long) and the other must be a sequence. In the\n' - 'former case, the numbers are converted to a common type and then\n' - 'multiplied together. In the latter case, sequence repetition is\n' - 'performed; a negative repetition factor yields an empty sequence.\n' - '\n' - 'The "/" (division) and "//" (floor division) operators yield the\n' - 'quotient of their arguments. The numeric arguments are first\n' - 'converted to a common type. Plain or long integer division yields ' - 'an\n' - 'integer of the same type; the result is that of mathematical ' - 'division\n' - "with the 'floor' function applied to the result. Division by zero\n" - 'raises the "ZeroDivisionError" exception.\n' - '\n' - 'The "%" (modulo) operator yields the remainder from the division ' - 'of\n' - 'the first argument by the second. The numeric arguments are ' - 'first\n' - 'converted to a common type. A zero right argument raises the\n' - '"ZeroDivisionError" exception. The arguments may be floating ' - 'point\n' - 'numbers, e.g., "3.14%0.7" equals "0.34" (since "3.14" equals ' - '"4*0.7 +\n' - '0.34".) The modulo operator always yields a result with the same ' - 'sign\n' - 'as its second operand (or zero); the absolute value of the result ' - 'is\n' - 'strictly smaller than the absolute value of the second operand ' - '[2].\n' - '\n' - 'The integer division and modulo operators are connected by the\n' - 'following identity: "x == (x/y)*y + (x%y)". Integer division and\n' - 'modulo are also connected with the built-in function "divmod()":\n' - '"divmod(x, y) == (x/y, x%y)". These identities don\'t hold for\n' - 'floating point numbers; there similar identities hold ' - 'approximately\n' - 'where "x/y" is replaced by "floor(x/y)" or "floor(x/y) - 1" [3].\n' - '\n' - 'In addition to performing the modulo operation on numbers, the ' - '"%"\n' - 'operator is also overloaded by string and unicode objects to ' - 'perform\n' - 'string formatting (also known as interpolation). The syntax for ' - 'string\n' - 'formatting is described in the Python Library Reference, section\n' - 'String Formatting Operations.\n' - '\n' - 'Deprecated since version 2.3: The floor division operator, the ' - 'modulo\n' - 'operator, and the "divmod()" function are no longer defined for\n' - 'complex numbers. Instead, convert to a floating point number ' - 'using\n' - 'the "abs()" function if appropriate.\n' - '\n' - 'The "+" (addition) operator yields the sum of its arguments. The\n' - 'arguments must either both be numbers or both sequences of the ' - 'same\n' - 'type. In the former case, the numbers are converted to a common ' - 'type\n' - 'and then added together. In the latter case, the sequences are\n' - 'concatenated.\n' - '\n' - 'The "-" (subtraction) operator yields the difference of its ' - 'arguments.\n' - 'The numeric arguments are first converted to a common type.\n', - 'bitwise': '\n' - 'Binary bitwise operations\n' - '*************************\n' - '\n' - 'Each of the three bitwise operations has a different priority ' - 'level:\n' - '\n' - ' and_expr ::= shift_expr | and_expr "&" shift_expr\n' - ' xor_expr ::= and_expr | xor_expr "^" and_expr\n' - ' or_expr ::= xor_expr | or_expr "|" xor_expr\n' - '\n' - 'The "&" operator yields the bitwise AND of its arguments, which ' - 'must\n' - 'be plain or long integers. The arguments are converted to a ' - 'common\n' - 'type.\n' - '\n' - 'The "^" operator yields the bitwise XOR (exclusive OR) of its\n' - 'arguments, which must be plain or long integers. The arguments ' - 'are\n' - 'converted to a common type.\n' - '\n' - 'The "|" operator yields the bitwise (inclusive) OR of its ' - 'arguments,\n' - 'which must be plain or long integers. The arguments are ' - 'converted to\n' - 'a common type.\n', - 'bltin-code-objects': '\n' - 'Code Objects\n' - '************\n' - '\n' - 'Code objects are used by the implementation to ' - 'represent "pseudo-\n' - 'compiled" executable Python code such as a function ' - 'body. They differ\n' - "from function objects because they don't contain a " - 'reference to their\n' - 'global execution environment. Code objects are ' - 'returned by the built-\n' - 'in "compile()" function and can be extracted from ' - 'function objects\n' - 'through their "func_code" attribute. See also the ' - '"code" module.\n' - '\n' - 'A code object can be executed or evaluated by passing ' - 'it (instead of a\n' - 'source string) to the "exec" statement or the built-in ' - '"eval()"\n' - 'function.\n' - '\n' - 'See The standard type hierarchy for more ' - 'information.\n', - 'bltin-ellipsis-object': '\n' - 'The Ellipsis Object\n' - '*******************\n' - '\n' - 'This object is used by extended slice notation (see ' - 'Slicings). It\n' - 'supports no special operations. There is exactly ' - 'one ellipsis object,\n' - 'named "Ellipsis" (a built-in name).\n' - '\n' - 'It is written as "Ellipsis". When in a subscript, ' - 'it can also be\n' - 'written as "...", for example "seq[...]".\n', - 'bltin-file-objects': '\n' - 'File Objects\n' - '************\n' - '\n' - 'File objects are implemented using C\'s "stdio" ' - 'package and can be\n' - 'created with the built-in "open()" function. File ' - 'objects are also\n' - 'returned by some other built-in functions and methods, ' - 'such as\n' - '"os.popen()" and "os.fdopen()" and the "makefile()" ' - 'method of socket\n' - 'objects. Temporary files can be created using the ' - '"tempfile" module,\n' - 'and high-level file operations such as copying, ' - 'moving, and deleting\n' - 'files and directories can be achieved with the ' - '"shutil" module.\n' - '\n' - 'When a file operation fails for an I/O-related reason, ' - 'the exception\n' - '"IOError" is raised. This includes situations where ' - 'the operation is\n' - 'not defined for some reason, like "seek()" on a tty ' - 'device or writing\n' - 'a file opened for reading.\n' - '\n' - 'Files have the following methods:\n' - '\n' - 'file.close()\n' - '\n' - ' Close the file. A closed file cannot be read or ' - 'written any more.\n' - ' Any operation which requires that the file be open ' - 'will raise a\n' - ' "ValueError" after the file has been closed. ' - 'Calling "close()"\n' - ' more than once is allowed.\n' - '\n' - ' As of Python 2.5, you can avoid having to call this ' - 'method\n' - ' explicitly if you use the "with" statement. For ' - 'example, the\n' - ' following code will automatically close *f* when ' - 'the "with" block\n' - ' is exited:\n' - '\n' - ' from __future__ import with_statement # This ' - "isn't required in Python 2.6\n" - '\n' - ' with open("hello.txt") as f:\n' - ' for line in f:\n' - ' print line,\n' - '\n' - ' In older versions of Python, you would have needed ' - 'to do this to\n' - ' get the same effect:\n' - '\n' - ' f = open("hello.txt")\n' - ' try:\n' - ' for line in f:\n' - ' print line,\n' - ' finally:\n' - ' f.close()\n' - '\n' - ' Note: Not all "file-like" types in Python support ' - 'use as a\n' - ' context manager for the "with" statement. If ' - 'your code is\n' - ' intended to work with any file-like object, you ' - 'can use the\n' - ' function "contextlib.closing()" instead of using ' - 'the object\n' - ' directly.\n' - '\n' - 'file.flush()\n' - '\n' - ' Flush the internal buffer, like "stdio"\'s ' - '"fflush()". This may be\n' - ' a no-op on some file-like objects.\n' - '\n' - ' Note: "flush()" does not necessarily write the ' - "file's data to\n" - ' disk. Use "flush()" followed by "os.fsync()" to ' - 'ensure this\n' - ' behavior.\n' - '\n' - 'file.fileno()\n' - '\n' - ' Return the integer "file descriptor" that is used ' - 'by the underlying\n' - ' implementation to request I/O operations from the ' - 'operating system.\n' - ' This can be useful for other, lower level ' - 'interfaces that use file\n' - ' descriptors, such as the "fcntl" module or ' - '"os.read()" and friends.\n' - '\n' - ' Note: File-like objects which do not have a real ' - 'file descriptor\n' - ' should *not* provide this method!\n' - '\n' - 'file.isatty()\n' - '\n' - ' Return "True" if the file is connected to a ' - 'tty(-like) device, else\n' - ' "False".\n' - '\n' - ' Note: If a file-like object is not associated with ' - 'a real file,\n' - ' this method should *not* be implemented.\n' - '\n' - 'file.next()\n' - '\n' - ' A file object is its own iterator, for example ' - '"iter(f)" returns\n' - ' *f* (unless *f* is closed). When a file is used as ' - 'an iterator,\n' - ' typically in a "for" loop (for example, "for line ' - 'in f: print\n' - ' line.strip()"), the "next()" method is called ' - 'repeatedly. This\n' - ' method returns the next input line, or raises ' - '"StopIteration" when\n' - ' EOF is hit when the file is open for reading ' - '(behavior is undefined\n' - ' when the file is open for writing). In order to ' - 'make a "for" loop\n' - ' the most efficient way of looping over the lines of ' - 'a file (a very\n' - ' common operation), the "next()" method uses a ' - 'hidden read-ahead\n' - ' buffer. As a consequence of using a read-ahead ' - 'buffer, combining\n' - ' "next()" with other file methods (like ' - '"readline()") does not work\n' - ' right. However, using "seek()" to reposition the ' - 'file to an\n' - ' absolute position will flush the read-ahead ' - 'buffer.\n' - '\n' - ' New in version 2.3.\n' - '\n' - 'file.read([size])\n' - '\n' - ' Read at most *size* bytes from the file (less if ' - 'the read hits EOF\n' - ' before obtaining *size* bytes). If the *size* ' - 'argument is negative\n' - ' or omitted, read all data until EOF is reached. ' - 'The bytes are\n' - ' returned as a string object. An empty string is ' - 'returned when EOF\n' - ' is encountered immediately. (For certain files, ' - 'like ttys, it\n' - ' makes sense to continue reading after an EOF is ' - 'hit.) Note that\n' - ' this method may call the underlying C function ' - '"fread()" more than\n' - ' once in an effort to acquire as close to *size* ' - 'bytes as possible.\n' - ' Also note that when in non-blocking mode, less data ' - 'than was\n' - ' requested may be returned, even if no *size* ' - 'parameter was given.\n' - '\n' - ' Note: This function is simply a wrapper for the ' - 'underlying\n' - ' "fread()" C function, and will behave the same in ' - 'corner cases,\n' - ' such as whether the EOF value is cached.\n' - '\n' - 'file.readline([size])\n' - '\n' - ' Read one entire line from the file. A trailing ' - 'newline character\n' - ' is kept in the string (but may be absent when a ' - 'file ends with an\n' - ' incomplete line). [6] If the *size* argument is ' - 'present and non-\n' - ' negative, it is a maximum byte count (including the ' - 'trailing\n' - ' newline) and an incomplete line may be returned. ' - 'When *size* is not\n' - ' 0, an empty string is returned *only* when EOF is ' - 'encountered\n' - ' immediately.\n' - '\n' - ' Note: Unlike "stdio"\'s "fgets()", the returned ' - 'string contains\n' - ' null characters ("\'\\0\'") if they occurred in ' - 'the input.\n' - '\n' - 'file.readlines([sizehint])\n' - '\n' - ' Read until EOF using "readline()" and return a list ' - 'containing the\n' - ' lines thus read. If the optional *sizehint* ' - 'argument is present,\n' - ' instead of reading up to EOF, whole lines totalling ' - 'approximately\n' - ' *sizehint* bytes (possibly after rounding up to an ' - 'internal buffer\n' - ' size) are read. Objects implementing a file-like ' - 'interface may\n' - ' choose to ignore *sizehint* if it cannot be ' - 'implemented, or cannot\n' - ' be implemented efficiently.\n' - '\n' - 'file.xreadlines()\n' - '\n' - ' This method returns the same thing as "iter(f)".\n' - '\n' - ' New in version 2.1.\n' - '\n' - ' Deprecated since version 2.3: Use "for line in ' - 'file" instead.\n' - '\n' - 'file.seek(offset[, whence])\n' - '\n' - ' Set the file\'s current position, like "stdio"\'s ' - '"fseek()". The\n' - ' *whence* argument is optional and defaults to ' - '"os.SEEK_SET" or "0"\n' - ' (absolute file positioning); other values are ' - '"os.SEEK_CUR" or "1"\n' - ' (seek relative to the current position) and ' - '"os.SEEK_END" or "2"\n' - " (seek relative to the file's end). There is no " - 'return value.\n' - '\n' - ' For example, "f.seek(2, os.SEEK_CUR)" advances the ' - 'position by two\n' - ' and "f.seek(-3, os.SEEK_END)" sets the position to ' - 'the third to\n' - ' last.\n' - '\n' - ' Note that if the file is opened for appending (mode ' - '"\'a\'" or\n' - ' "\'a+\'"), any "seek()" operations will be undone ' - 'at the next write.\n' - ' If the file is only opened for writing in append ' - 'mode (mode "\'a\'"),\n' - ' this method is essentially a no-op, but it remains ' - 'useful for files\n' - ' opened in append mode with reading enabled (mode ' - '"\'a+\'"). If the\n' - ' file is opened in text mode (without "\'b\'"), only ' - 'offsets returned\n' - ' by "tell()" are legal. Use of other offsets causes ' - 'undefined\n' - ' behavior.\n' - '\n' - ' Note that not all file objects are seekable.\n' - '\n' - ' Changed in version 2.6: Passing float values as ' - 'offset has been\n' - ' deprecated.\n' - '\n' - 'file.tell()\n' - '\n' - " Return the file's current position, like " - '"stdio"\'s "ftell()".\n' - '\n' - ' Note: On Windows, "tell()" can return illegal ' - 'values (after an\n' - ' "fgets()") when reading files with Unix-style ' - 'line-endings. Use\n' - ' binary mode ("\'rb\'") to circumvent this ' - 'problem.\n' - '\n' - 'file.truncate([size])\n' - '\n' - " Truncate the file's size. If the optional *size* " - 'argument is\n' - ' present, the file is truncated to (at most) that ' - 'size. The size\n' - ' defaults to the current position. The current file ' - 'position is not\n' - ' changed. Note that if a specified size exceeds the ' - "file's current\n" - ' size, the result is platform-dependent: ' - 'possibilities include that\n' - ' the file may remain unchanged, increase to the ' - 'specified size as if\n' - ' zero-filled, or increase to the specified size with ' - 'undefined new\n' - ' content. Availability: Windows, many Unix ' - 'variants.\n' - '\n' - 'file.write(str)\n' - '\n' - ' Write a string to the file. There is no return ' - 'value. Due to\n' - ' buffering, the string may not actually show up in ' - 'the file until\n' - ' the "flush()" or "close()" method is called.\n' - '\n' - 'file.writelines(sequence)\n' - '\n' - ' Write a sequence of strings to the file. The ' - 'sequence can be any\n' - ' iterable object producing strings, typically a list ' - 'of strings.\n' - ' There is no return value. (The name is intended to ' - 'match\n' - ' "readlines()"; "writelines()" does not add line ' - 'separators.)\n' - '\n' - 'Files support the iterator protocol. Each iteration ' - 'returns the same\n' - 'result as "readline()", and iteration ends when the ' - '"readline()"\n' - 'method returns an empty string.\n' - '\n' - 'File objects also offer a number of other interesting ' - 'attributes.\n' - 'These are not required for file-like objects, but ' - 'should be\n' - 'implemented if they make sense for the particular ' - 'object.\n' - '\n' - 'file.closed\n' - '\n' - ' bool indicating the current state of the file ' - 'object. This is a\n' - ' read-only attribute; the "close()" method changes ' - 'the value. It may\n' - ' not be available on all file-like objects.\n' - '\n' - 'file.encoding\n' - '\n' - ' The encoding that this file uses. When Unicode ' - 'strings are written\n' - ' to a file, they will be converted to byte strings ' - 'using this\n' - ' encoding. In addition, when the file is connected ' - 'to a terminal,\n' - ' the attribute gives the encoding that the terminal ' - 'is likely to use\n' - ' (that information might be incorrect if the user ' - 'has misconfigured\n' - ' the terminal). The attribute is read-only and may ' - 'not be present\n' - ' on all file-like objects. It may also be "None", in ' - 'which case the\n' - ' file uses the system default encoding for ' - 'converting Unicode\n' - ' strings.\n' - '\n' - ' New in version 2.3.\n' - '\n' - 'file.errors\n' - '\n' - ' The Unicode error handler used along with the ' - 'encoding.\n' - '\n' - ' New in version 2.6.\n' - '\n' - 'file.mode\n' - '\n' - ' The I/O mode for the file. If the file was created ' - 'using the\n' - ' "open()" built-in function, this will be the value ' - 'of the *mode*\n' - ' parameter. This is a read-only attribute and may ' - 'not be present on\n' - ' all file-like objects.\n' - '\n' - 'file.name\n' - '\n' - ' If the file object was created using "open()", the ' - 'name of the\n' - ' file. Otherwise, some string that indicates the ' - 'source of the file\n' - ' object, of the form "<...>". This is a read-only ' - 'attribute and may\n' - ' not be present on all file-like objects.\n' - '\n' - 'file.newlines\n' - '\n' - ' If Python was built with *universal newlines* ' - 'enabled (the default)\n' - ' this read-only attribute exists, and for files ' - 'opened in universal\n' - ' newline read mode it keeps track of the types of ' - 'newlines\n' - ' encountered while reading the file. The values it ' - 'can take are\n' - ' "\'\\r\'", "\'\\n\'", "\'\\r\\n\'", "None" ' - '(unknown, no newlines read yet) or\n' - ' a tuple containing all the newline types seen, to ' - 'indicate that\n' - ' multiple newline conventions were encountered. For ' - 'files not opened\n' - ' in universal newlines read mode the value of this ' - 'attribute will be\n' - ' "None".\n' - '\n' - 'file.softspace\n' - '\n' - ' Boolean that indicates whether a space character ' - 'needs to be\n' - ' printed before another value when using the "print" ' - 'statement.\n' - ' Classes that are trying to simulate a file object ' - 'should also have\n' - ' a writable "softspace" attribute, which should be ' - 'initialized to\n' - ' zero. This will be automatic for most classes ' - 'implemented in\n' - ' Python (care may be needed for objects that ' - 'override attribute\n' - ' access); types implemented in C will have to ' - 'provide a writable\n' - ' "softspace" attribute.\n' - '\n' - ' Note: This attribute is not used to control the ' - '"print"\n' - ' statement, but to allow the implementation of ' - '"print" to keep\n' - ' track of its internal state.\n', - 'bltin-null-object': '\n' - 'The Null Object\n' - '***************\n' - '\n' - "This object is returned by functions that don't " - 'explicitly return a\n' - 'value. It supports no special operations. There is ' - 'exactly one null\n' - 'object, named "None" (a built-in name).\n' - '\n' - 'It is written as "None".\n', - 'bltin-type-objects': '\n' - 'Type Objects\n' - '************\n' - '\n' - 'Type objects represent the various object types. An ' - "object's type is\n" - 'accessed by the built-in function "type()". There are ' - 'no special\n' - 'operations on types. The standard module "types" ' - 'defines names for\n' - 'all standard built-in types.\n' - '\n' - 'Types are written like this: "<type \'int\'>".\n', - 'booleans': '\n' - 'Boolean operations\n' - '******************\n' - '\n' - ' or_test ::= and_test | or_test "or" and_test\n' - ' and_test ::= not_test | and_test "and" not_test\n' - ' not_test ::= comparison | "not" not_test\n' - '\n' - 'In the context of Boolean operations, and also when expressions ' - 'are\n' - 'used by control flow statements, the following values are ' - 'interpreted\n' - 'as false: "False", "None", numeric zero of all types, and empty\n' - 'strings and containers (including strings, tuples, lists,\n' - 'dictionaries, sets and frozensets). All other values are ' - 'interpreted\n' - 'as true. (See the "__nonzero__()" special method for a way to ' - 'change\n' - 'this.)\n' - '\n' - 'The operator "not" yields "True" if its argument is false, ' - '"False"\n' - 'otherwise.\n' - '\n' - 'The expression "x and y" first evaluates *x*; if *x* is false, ' - 'its\n' - 'value is returned; otherwise, *y* is evaluated and the resulting ' - 'value\n' - 'is returned.\n' - '\n' - 'The expression "x or y" first evaluates *x*; if *x* is true, its ' - 'value\n' - 'is returned; otherwise, *y* is evaluated and the resulting value ' - 'is\n' - 'returned.\n' - '\n' - '(Note that neither "and" nor "or" restrict the value and type ' - 'they\n' - 'return to "False" and "True", but rather return the last ' - 'evaluated\n' - 'argument. This is sometimes useful, e.g., if "s" is a string ' - 'that\n' - 'should be replaced by a default value if it is empty, the ' - 'expression\n' - '"s or \'foo\'" yields the desired value. Because "not" has to ' - 'invent a\n' - 'value anyway, it does not bother to return a value of the same ' - 'type as\n' - 'its argument, so e.g., "not \'foo\'" yields "False", not ' - '"\'\'".)\n', - 'break': '\n' - 'The "break" statement\n' - '*********************\n' - '\n' - ' break_stmt ::= "break"\n' - '\n' - '"break" may only occur syntactically nested in a "for" or "while"\n' - 'loop, but not nested in a function or class definition within that\n' - 'loop.\n' - '\n' - 'It terminates the nearest enclosing loop, skipping the optional ' - '"else"\n' - 'clause if the loop has one.\n' - '\n' - 'If a "for" loop is terminated by "break", the loop control target\n' - 'keeps its current value.\n' - '\n' - 'When "break" passes control out of a "try" statement with a ' - '"finally"\n' - 'clause, that "finally" clause is executed before really leaving ' - 'the\n' - 'loop.\n', - 'callable-types': '\n' - 'Emulating callable objects\n' - '**************************\n' - '\n' - 'object.__call__(self[, args...])\n' - '\n' - ' Called when the instance is "called" as a function; if ' - 'this method\n' - ' is defined, "x(arg1, arg2, ...)" is a shorthand for\n' - ' "x.__call__(arg1, arg2, ...)".\n', - 'calls': '\n' - 'Calls\n' - '*****\n' - '\n' - 'A call calls a callable object (e.g., a *function*) with a ' - 'possibly\n' - 'empty series of *arguments*:\n' - '\n' - ' call ::= primary "(" [argument_list [","]\n' - ' | expression genexpr_for] ")"\n' - ' argument_list ::= positional_arguments ["," ' - 'keyword_arguments]\n' - ' ["," "*" expression] ["," ' - 'keyword_arguments]\n' - ' ["," "**" expression]\n' - ' | keyword_arguments ["," "*" expression]\n' - ' ["," "**" expression]\n' - ' | "*" expression ["," keyword_arguments] ["," ' - '"**" expression]\n' - ' | "**" expression\n' - ' positional_arguments ::= expression ("," expression)*\n' - ' keyword_arguments ::= keyword_item ("," keyword_item)*\n' - ' keyword_item ::= identifier "=" expression\n' - '\n' - 'A trailing comma may be present after the positional and keyword\n' - 'arguments but does not affect the semantics.\n' - '\n' - 'The primary must evaluate to a callable object (user-defined\n' - 'functions, built-in functions, methods of built-in objects, class\n' - 'objects, methods of class instances, and certain class instances\n' - 'themselves are callable; extensions may define additional callable\n' - 'object types). All argument expressions are evaluated before the ' - 'call\n' - 'is attempted. Please refer to section Function definitions for ' - 'the\n' - 'syntax of formal *parameter* lists.\n' - '\n' - 'If keyword arguments are present, they are first converted to\n' - 'positional arguments, as follows. First, a list of unfilled slots ' - 'is\n' - 'created for the formal parameters. If there are N positional\n' - 'arguments, they are placed in the first N slots. Next, for each\n' - 'keyword argument, the identifier is used to determine the\n' - 'corresponding slot (if the identifier is the same as the first ' - 'formal\n' - 'parameter name, the first slot is used, and so on). If the slot ' - 'is\n' - 'already filled, a "TypeError" exception is raised. Otherwise, the\n' - 'value of the argument is placed in the slot, filling it (even if ' - 'the\n' - 'expression is "None", it fills the slot). When all arguments have\n' - 'been processed, the slots that are still unfilled are filled with ' - 'the\n' - 'corresponding default value from the function definition. ' - '(Default\n' - 'values are calculated, once, when the function is defined; thus, a\n' - 'mutable object such as a list or dictionary used as default value ' - 'will\n' - "be shared by all calls that don't specify an argument value for " - 'the\n' - 'corresponding slot; this should usually be avoided.) If there are ' - 'any\n' - 'unfilled slots for which no default value is specified, a ' - '"TypeError"\n' - 'exception is raised. Otherwise, the list of filled slots is used ' - 'as\n' - 'the argument list for the call.\n' - '\n' - '**CPython implementation detail:** An implementation may provide\n' - 'built-in functions whose positional parameters do not have names, ' - 'even\n' - "if they are 'named' for the purpose of documentation, and which\n" - 'therefore cannot be supplied by keyword. In CPython, this is the ' - 'case\n' - 'for functions implemented in C that use "PyArg_ParseTuple()" to ' - 'parse\n' - 'their arguments.\n' - '\n' - 'If there are more positional arguments than there are formal ' - 'parameter\n' - 'slots, a "TypeError" exception is raised, unless a formal ' - 'parameter\n' - 'using the syntax "*identifier" is present; in this case, that ' - 'formal\n' - 'parameter receives a tuple containing the excess positional ' - 'arguments\n' - '(or an empty tuple if there were no excess positional arguments).\n' - '\n' - 'If any keyword argument does not correspond to a formal parameter\n' - 'name, a "TypeError" exception is raised, unless a formal parameter\n' - 'using the syntax "**identifier" is present; in this case, that ' - 'formal\n' - 'parameter receives a dictionary containing the excess keyword\n' - 'arguments (using the keywords as keys and the argument values as\n' - 'corresponding values), or a (new) empty dictionary if there were ' - 'no\n' - 'excess keyword arguments.\n' - '\n' - 'If the syntax "*expression" appears in the function call, ' - '"expression"\n' - 'must evaluate to an iterable. Elements from this iterable are ' - 'treated\n' - 'as if they were additional positional arguments; if there are\n' - 'positional arguments *x1*, ..., *xN*, and "expression" evaluates to ' - 'a\n' - 'sequence *y1*, ..., *yM*, this is equivalent to a call with M+N\n' - 'positional arguments *x1*, ..., *xN*, *y1*, ..., *yM*.\n' - '\n' - 'A consequence of this is that although the "*expression" syntax ' - 'may\n' - 'appear *after* some keyword arguments, it is processed *before* ' - 'the\n' - 'keyword arguments (and the "**expression" argument, if any -- see\n' - 'below). So:\n' - '\n' - ' >>> def f(a, b):\n' - ' ... print a, b\n' - ' ...\n' - ' >>> f(b=1, *(2,))\n' - ' 2 1\n' - ' >>> f(a=1, *(2,))\n' - ' Traceback (most recent call last):\n' - ' File "<stdin>", line 1, in <module>\n' - " TypeError: f() got multiple values for keyword argument 'a'\n" - ' >>> f(1, *(2,))\n' - ' 1 2\n' - '\n' - 'It is unusual for both keyword arguments and the "*expression" ' - 'syntax\n' - 'to be used in the same call, so in practice this confusion does ' - 'not\n' - 'arise.\n' - '\n' - 'If the syntax "**expression" appears in the function call,\n' - '"expression" must evaluate to a mapping, the contents of which are\n' - 'treated as additional keyword arguments. In the case of a keyword\n' - 'appearing in both "expression" and as an explicit keyword argument, ' - 'a\n' - '"TypeError" exception is raised.\n' - '\n' - 'Formal parameters using the syntax "*identifier" or "**identifier"\n' - 'cannot be used as positional argument slots or as keyword argument\n' - 'names. Formal parameters using the syntax "(sublist)" cannot be ' - 'used\n' - 'as keyword argument names; the outermost sublist corresponds to a\n' - 'single unnamed argument slot, and the argument value is assigned ' - 'to\n' - 'the sublist using the usual tuple assignment rules after all other\n' - 'parameter processing is done.\n' - '\n' - 'A call always returns some value, possibly "None", unless it raises ' - 'an\n' - 'exception. How this value is computed depends on the type of the\n' - 'callable object.\n' - '\n' - 'If it is---\n' - '\n' - 'a user-defined function:\n' - ' The code block for the function is executed, passing it the\n' - ' argument list. The first thing the code block will do is bind ' - 'the\n' - ' formal parameters to the arguments; this is described in ' - 'section\n' - ' Function definitions. When the code block executes a "return"\n' - ' statement, this specifies the return value of the function ' - 'call.\n' - '\n' - 'a built-in function or method:\n' - ' The result is up to the interpreter; see Built-in Functions for ' - 'the\n' - ' descriptions of built-in functions and methods.\n' - '\n' - 'a class object:\n' - ' A new instance of that class is returned.\n' - '\n' - 'a class instance method:\n' - ' The corresponding user-defined function is called, with an ' - 'argument\n' - ' list that is one longer than the argument list of the call: the\n' - ' instance becomes the first argument.\n' - '\n' - 'a class instance:\n' - ' The class must define a "__call__()" method; the effect is then ' - 'the\n' - ' same as if that method was called.\n', - 'class': '\n' - 'Class definitions\n' - '*****************\n' - '\n' - 'A class definition defines a class object (see section The ' - 'standard\n' - 'type hierarchy):\n' - '\n' - ' classdef ::= "class" classname [inheritance] ":" suite\n' - ' inheritance ::= "(" [expression_list] ")"\n' - ' classname ::= identifier\n' - '\n' - 'A class definition is an executable statement. It first evaluates ' - 'the\n' - 'inheritance list, if present. Each item in the inheritance list\n' - 'should evaluate to a class object or class type which allows\n' - "subclassing. The class's suite is then executed in a new " - 'execution\n' - 'frame (see section Naming and binding), using a newly created ' - 'local\n' - 'namespace and the original global namespace. (Usually, the suite\n' - "contains only function definitions.) When the class's suite " - 'finishes\n' - 'execution, its execution frame is discarded but its local namespace ' - 'is\n' - 'saved. [4] A class object is then created using the inheritance ' - 'list\n' - 'for the base classes and the saved local namespace for the ' - 'attribute\n' - 'dictionary. The class name is bound to this class object in the\n' - 'original local namespace.\n' - '\n' - "**Programmer's note:** Variables defined in the class definition " - 'are\n' - 'class variables; they are shared by all instances. To create ' - 'instance\n' - 'variables, they can be set in a method with "self.name = value". ' - 'Both\n' - 'class and instance variables are accessible through the notation\n' - '""self.name"", and an instance variable hides a class variable ' - 'with\n' - 'the same name when accessed in this way. Class variables can be ' - 'used\n' - 'as defaults for instance variables, but using mutable values there ' - 'can\n' - 'lead to unexpected results. For *new-style class*es, descriptors ' - 'can\n' - 'be used to create instance variables with different implementation\n' - 'details.\n' - '\n' - 'Class definitions, like function definitions, may be wrapped by one ' - 'or\n' - 'more *decorator* expressions. The evaluation rules for the ' - 'decorator\n' - 'expressions are the same as for functions. The result must be a ' - 'class\n' - 'object, which is then bound to the class name.\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] The exception is propagated to the invocation stack unless\n' - ' there is a "finally" clause which happens to raise another\n' - ' exception. That new exception causes the old one to be lost.\n' - '\n' - '[2] Currently, control "flows off the end" except in the case of\n' - ' an exception or the execution of a "return", "continue", or\n' - ' "break" statement.\n' - '\n' - '[3] A string literal appearing as the first statement in the\n' - ' function body is transformed into the function\'s "__doc__"\n' - " attribute and therefore the function's *docstring*.\n" - '\n' - '[4] A string literal appearing as the first statement in the class\n' - ' body is transformed into the namespace\'s "__doc__" item and\n' - " therefore the class's *docstring*.\n", - 'comparisons': '\n' - 'Comparisons\n' - '***********\n' - '\n' - 'Unlike C, all comparison operations in Python have the same ' - 'priority,\n' - 'which is lower than that of any arithmetic, shifting or ' - 'bitwise\n' - 'operation. Also unlike C, expressions like "a < b < c" have ' - 'the\n' - 'interpretation that is conventional in mathematics:\n' - '\n' - ' comparison ::= or_expr ( comp_operator or_expr )*\n' - ' comp_operator ::= "<" | ">" | "==" | ">=" | "<=" | "<>" | ' - '"!="\n' - ' | "is" ["not"] | ["not"] "in"\n' - '\n' - 'Comparisons yield boolean values: "True" or "False".\n' - '\n' - 'Comparisons can be chained arbitrarily, e.g., "x < y <= z" ' - 'is\n' - 'equivalent to "x < y and y <= z", except that "y" is ' - 'evaluated only\n' - 'once (but in both cases "z" is not evaluated at all when "x < ' - 'y" is\n' - 'found to be false).\n' - '\n' - 'Formally, if *a*, *b*, *c*, ..., *y*, *z* are expressions and ' - '*op1*,\n' - '*op2*, ..., *opN* are comparison operators, then "a op1 b op2 ' - 'c ... y\n' - 'opN z" is equivalent to "a op1 b and b op2 c and ... y opN ' - 'z", except\n' - 'that each expression is evaluated at most once.\n' - '\n' - 'Note that "a op1 b op2 c" doesn\'t imply any kind of ' - 'comparison between\n' - '*a* and *c*, so that, e.g., "x < y > z" is perfectly legal ' - '(though\n' - 'perhaps not pretty).\n' - '\n' - 'The forms "<>" and "!=" are equivalent; for consistency with ' - 'C, "!="\n' - 'is preferred; where "!=" is mentioned below "<>" is also ' - 'accepted.\n' - 'The "<>" spelling is considered obsolescent.\n' - '\n' - '\n' - 'Value comparisons\n' - '=================\n' - '\n' - 'The operators "<", ">", "==", ">=", "<=", and "!=" compare ' - 'the values\n' - 'of two objects. The objects do not need to have the same ' - 'type.\n' - '\n' - 'Chapter Objects, values and types states that objects have a ' - 'value (in\n' - 'addition to type and identity). The value of an object is a ' - 'rather\n' - 'abstract notion in Python: For example, there is no canonical ' - 'access\n' - "method for an object's value. Also, there is no requirement " - 'that the\n' - 'value of an object should be constructed in a particular way, ' - 'e.g.\n' - 'comprised of all its data attributes. Comparison operators ' - 'implement a\n' - 'particular notion of what the value of an object is. One can ' - 'think of\n' - 'them as defining the value of an object indirectly, by means ' - 'of their\n' - 'comparison implementation.\n' - '\n' - 'Types can customize their comparison behavior by implementing ' - 'a\n' - '"__cmp__()" method or *rich comparison methods* like ' - '"__lt__()",\n' - 'described in Basic customization.\n' - '\n' - 'The default behavior for equality comparison ("==" and "!=") ' - 'is based\n' - 'on the identity of the objects. Hence, equality comparison ' - 'of\n' - 'instances with the same identity results in equality, and ' - 'equality\n' - 'comparison of instances with different identities results in\n' - 'inequality. A motivation for this default behavior is the ' - 'desire that\n' - 'all objects should be reflexive (i.e. "x is y" implies "x == ' - 'y").\n' - '\n' - 'The default order comparison ("<", ">", "<=", and ">=") gives ' - 'a\n' - 'consistent but arbitrary order.\n' - '\n' - '(This unusual definition of comparison was used to simplify ' - 'the\n' - 'definition of operations like sorting and the "in" and "not ' - 'in"\n' - 'operators. In the future, the comparison rules for objects ' - 'of\n' - 'different types are likely to change.)\n' - '\n' - 'The behavior of the default equality comparison, that ' - 'instances with\n' - 'different identities are always unequal, may be in contrast ' - 'to what\n' - 'types will need that have a sensible definition of object ' - 'value and\n' - 'value-based equality. Such types will need to customize ' - 'their\n' - 'comparison behavior, and in fact, a number of built-in types ' - 'have done\n' - 'that.\n' - '\n' - 'The following list describes the comparison behavior of the ' - 'most\n' - 'important built-in types.\n' - '\n' - '* Numbers of built-in numeric types (Numeric Types --- int, ' - 'float,\n' - ' long, complex) and of the standard library types\n' - ' "fractions.Fraction" and "decimal.Decimal" can be compared ' - 'within\n' - ' and across their types, with the restriction that complex ' - 'numbers do\n' - ' not support order comparison. Within the limits of the ' - 'types\n' - ' involved, they compare mathematically (algorithmically) ' - 'correct\n' - ' without loss of precision.\n' - '\n' - '* Strings (instances of "str" or "unicode") compare\n' - ' lexicographically using the numeric equivalents (the result ' - 'of the\n' - ' built-in function "ord()") of their characters. [4] When ' - 'comparing\n' - ' an 8-bit string and a Unicode string, the 8-bit string is ' - 'converted\n' - ' to Unicode. If the conversion fails, the strings are ' - 'considered\n' - ' unequal.\n' - '\n' - '* Instances of "tuple" or "list" can be compared only within ' - 'each of\n' - ' their types. Equality comparison across these types ' - 'results in\n' - ' unequality, and ordering comparison across these types ' - 'gives an\n' - ' arbitrary order.\n' - '\n' - ' These sequences compare lexicographically using comparison ' - 'of\n' - ' corresponding elements, whereby reflexivity of the elements ' - 'is\n' - ' enforced.\n' - '\n' - ' In enforcing reflexivity of elements, the comparison of ' - 'collections\n' - ' assumes that for a collection element "x", "x == x" is ' - 'always true.\n' - ' Based on that assumption, element identity is compared ' - 'first, and\n' - ' element comparison is performed only for distinct ' - 'elements. This\n' - ' approach yields the same result as a strict element ' - 'comparison\n' - ' would, if the compared elements are reflexive. For ' - 'non-reflexive\n' - ' elements, the result is different than for strict element\n' - ' comparison.\n' - '\n' - ' Lexicographical comparison between built-in collections ' - 'works as\n' - ' follows:\n' - '\n' - ' * For two collections to compare equal, they must be of the ' - 'same\n' - ' type, have the same length, and each pair of ' - 'corresponding\n' - ' elements must compare equal (for example, "[1,2] == ' - '(1,2)" is\n' - ' false because the type is not the same).\n' - '\n' - ' * Collections are ordered the same as their first unequal ' - 'elements\n' - ' (for example, "cmp([1,2,x], [1,2,y])" returns the same ' - 'as\n' - ' "cmp(x,y)"). If a corresponding element does not exist, ' - 'the\n' - ' shorter collection is ordered first (for example, "[1,2] ' - '<\n' - ' [1,2,3]" is true).\n' - '\n' - '* Mappings (instances of "dict") compare equal if and only if ' - 'they\n' - ' have equal *(key, value)* pairs. Equality comparison of the ' - 'keys and\n' - ' values enforces reflexivity.\n' - '\n' - ' Outcomes other than equality are resolved consistently, but ' - 'are not\n' - ' otherwise defined. [5]\n' - '\n' - '* Most other objects of built-in types compare unequal unless ' - 'they\n' - ' are the same object; the choice whether one object is ' - 'considered\n' - ' smaller or larger than another one is made arbitrarily but\n' - ' consistently within one execution of a program.\n' - '\n' - 'User-defined classes that customize their comparison behavior ' - 'should\n' - 'follow some consistency rules, if possible:\n' - '\n' - '* Equality comparison should be reflexive. In other words, ' - 'identical\n' - ' objects should compare equal:\n' - '\n' - ' "x is y" implies "x == y"\n' - '\n' - '* Comparison should be symmetric. In other words, the ' - 'following\n' - ' expressions should have the same result:\n' - '\n' - ' "x == y" and "y == x"\n' - '\n' - ' "x != y" and "y != x"\n' - '\n' - ' "x < y" and "y > x"\n' - '\n' - ' "x <= y" and "y >= x"\n' - '\n' - '* Comparison should be transitive. The following ' - '(non-exhaustive)\n' - ' examples illustrate that:\n' - '\n' - ' "x > y and y > z" implies "x > z"\n' - '\n' - ' "x < y and y <= z" implies "x < z"\n' - '\n' - '* Inverse comparison should result in the boolean negation. ' - 'In other\n' - ' words, the following expressions should have the same ' - 'result:\n' - '\n' - ' "x == y" and "not x != y"\n' - '\n' - ' "x < y" and "not x >= y" (for total ordering)\n' - '\n' - ' "x > y" and "not x <= y" (for total ordering)\n' - '\n' - ' The last two expressions apply to totally ordered ' - 'collections (e.g.\n' - ' to sequences, but not to sets or mappings). See also the\n' - ' "total_ordering()" decorator.\n' - '\n' - '* The "hash()" result should be consistent with equality. ' - 'Objects\n' - ' that are equal should either have the same hash value, or ' - 'be marked\n' - ' as unhashable.\n' - '\n' - 'Python does not enforce these consistency rules.\n' - '\n' - '\n' - 'Membership test operations\n' - '==========================\n' - '\n' - 'The operators "in" and "not in" test for membership. "x in ' - 's"\n' - 'evaluates to "True" if *x* is a member of *s*, and "False" ' - 'otherwise.\n' - '"x not in s" returns the negation of "x in s". All built-in ' - 'sequences\n' - 'and set types support this as well as dictionary, for which ' - '"in" tests\n' - 'whether the dictionary has a given key. For container types ' - 'such as\n' - 'list, tuple, set, frozenset, dict, or collections.deque, the\n' - 'expression "x in y" is equivalent to "any(x is e or x == e ' - 'for e in\n' - 'y)".\n' - '\n' - 'For the string and bytes types, "x in y" is "True" if and ' - 'only if *x*\n' - 'is a substring of *y*. An equivalent test is "y.find(x) != ' - '-1".\n' - 'Empty strings are always considered to be a substring of any ' - 'other\n' - 'string, so """ in "abc"" will return "True".\n' - '\n' - 'For user-defined classes which define the "__contains__()" ' - 'method, "x\n' - 'in y" returns "True" if "y.__contains__(x)" returns a true ' - 'value, and\n' - '"False" otherwise.\n' - '\n' - 'For user-defined classes which do not define "__contains__()" ' - 'but do\n' - 'define "__iter__()", "x in y" is "True" if some value "z" ' - 'with "x ==\n' - 'z" is produced while iterating over "y". If an exception is ' - 'raised\n' - 'during the iteration, it is as if "in" raised that ' - 'exception.\n' - '\n' - 'Lastly, the old-style iteration protocol is tried: if a class ' - 'defines\n' - '"__getitem__()", "x in y" is "True" if and only if there is a ' - 'non-\n' - 'negative integer index *i* such that "x == y[i]", and all ' - 'lower\n' - 'integer indices do not raise "IndexError" exception. (If any ' - 'other\n' - 'exception is raised, it is as if "in" raised that ' - 'exception).\n' - '\n' - 'The operator "not in" is defined to have the inverse true ' - 'value of\n' - '"in".\n' - '\n' - '\n' - 'Identity comparisons\n' - '====================\n' - '\n' - 'The operators "is" and "is not" test for object identity: "x ' - 'is y" is\n' - 'true if and only if *x* and *y* are the same object. "x is ' - 'not y"\n' - 'yields the inverse truth value. [6]\n', - 'compound': '\n' - 'Compound statements\n' - '*******************\n' - '\n' - 'Compound statements contain (groups of) other statements; they ' - 'affect\n' - 'or control the execution of those other statements in some way. ' - 'In\n' - 'general, compound statements span multiple lines, although in ' - 'simple\n' - 'incarnations a whole compound statement may be contained in one ' - 'line.\n' - '\n' - 'The "if", "while" and "for" statements implement traditional ' - 'control\n' - 'flow constructs. "try" specifies exception handlers and/or ' - 'cleanup\n' - 'code for a group of statements. Function and class definitions ' - 'are\n' - 'also syntactically compound statements.\n' - '\n' - "Compound statements consist of one or more 'clauses.' A clause\n" - "consists of a header and a 'suite.' The clause headers of a\n" - 'particular compound statement are all at the same indentation ' - 'level.\n' - 'Each clause header begins with a uniquely identifying keyword ' - 'and ends\n' - 'with a colon. A suite is a group of statements controlled by a\n' - 'clause. A suite can be one or more semicolon-separated simple\n' - 'statements on the same line as the header, following the ' - "header's\n" - 'colon, or it can be one or more indented statements on ' - 'subsequent\n' - 'lines. Only the latter form of suite can contain nested ' - 'compound\n' - "statements; the following is illegal, mostly because it wouldn't " - 'be\n' - 'clear to which "if" clause a following "else" clause would ' - 'belong:\n' - '\n' - ' if test1: if test2: print x\n' - '\n' - 'Also note that the semicolon binds tighter than the colon in ' - 'this\n' - 'context, so that in the following example, either all or none of ' - 'the\n' - '"print" statements are executed:\n' - '\n' - ' if x < y < z: print x; print y; print z\n' - '\n' - 'Summarizing:\n' - '\n' - ' compound_stmt ::= if_stmt\n' - ' | while_stmt\n' - ' | for_stmt\n' - ' | try_stmt\n' - ' | with_stmt\n' - ' | funcdef\n' - ' | classdef\n' - ' | decorated\n' - ' suite ::= stmt_list NEWLINE | NEWLINE INDENT ' - 'statement+ DEDENT\n' - ' statement ::= stmt_list NEWLINE | compound_stmt\n' - ' stmt_list ::= simple_stmt (";" simple_stmt)* [";"]\n' - '\n' - 'Note that statements always end in a "NEWLINE" possibly followed ' - 'by a\n' - '"DEDENT". Also note that optional continuation clauses always ' - 'begin\n' - 'with a keyword that cannot start a statement, thus there are no\n' - 'ambiguities (the \'dangling "else"\' problem is solved in Python ' - 'by\n' - 'requiring nested "if" statements to be indented).\n' - '\n' - 'The formatting of the grammar rules in the following sections ' - 'places\n' - 'each clause on a separate line for clarity.\n' - '\n' - '\n' - 'The "if" statement\n' - '==================\n' - '\n' - 'The "if" statement is used for conditional execution:\n' - '\n' - ' if_stmt ::= "if" expression ":" suite\n' - ' ( "elif" expression ":" suite )*\n' - ' ["else" ":" suite]\n' - '\n' - 'It selects exactly one of the suites by evaluating the ' - 'expressions one\n' - 'by one until one is found to be true (see section Boolean ' - 'operations\n' - 'for the definition of true and false); then that suite is ' - 'executed\n' - '(and no other part of the "if" statement is executed or ' - 'evaluated).\n' - 'If all expressions are false, the suite of the "else" clause, ' - 'if\n' - 'present, is executed.\n' - '\n' - '\n' - 'The "while" statement\n' - '=====================\n' - '\n' - 'The "while" statement is used for repeated execution as long as ' - 'an\n' - 'expression is true:\n' - '\n' - ' while_stmt ::= "while" expression ":" suite\n' - ' ["else" ":" suite]\n' - '\n' - 'This repeatedly tests the expression and, if it is true, ' - 'executes the\n' - 'first suite; if the expression is false (which may be the first ' - 'time\n' - 'it is tested) the suite of the "else" clause, if present, is ' - 'executed\n' - 'and the loop terminates.\n' - '\n' - 'A "break" statement executed in the first suite terminates the ' - 'loop\n' - 'without executing the "else" clause\'s suite. A "continue" ' - 'statement\n' - 'executed in the first suite skips the rest of the suite and goes ' - 'back\n' - 'to testing the expression.\n' - '\n' - '\n' - 'The "for" statement\n' - '===================\n' - '\n' - 'The "for" statement is used to iterate over the elements of a ' - 'sequence\n' - '(such as a string, tuple or list) or other iterable object:\n' - '\n' - ' for_stmt ::= "for" target_list "in" expression_list ":" ' - 'suite\n' - ' ["else" ":" suite]\n' - '\n' - 'The expression list is evaluated once; it should yield an ' - 'iterable\n' - 'object. An iterator is created for the result of the\n' - '"expression_list". The suite is then executed once for each ' - 'item\n' - 'provided by the iterator, in the order of ascending indices. ' - 'Each\n' - 'item in turn is assigned to the target list using the standard ' - 'rules\n' - 'for assignments, and then the suite is executed. When the items ' - 'are\n' - 'exhausted (which is immediately when the sequence is empty), the ' - 'suite\n' - 'in the "else" clause, if present, is executed, and the loop\n' - 'terminates.\n' - '\n' - 'A "break" statement executed in the first suite terminates the ' - 'loop\n' - 'without executing the "else" clause\'s suite. A "continue" ' - 'statement\n' - 'executed in the first suite skips the rest of the suite and ' - 'continues\n' - 'with the next item, or with the "else" clause if there was no ' - 'next\n' - 'item.\n' - '\n' - 'The suite may assign to the variable(s) in the target list; this ' - 'does\n' - 'not affect the next item assigned to it.\n' - '\n' - 'The target list is not deleted when the loop is finished, but if ' - 'the\n' - 'sequence is empty, it will not have been assigned to at all by ' - 'the\n' - 'loop. Hint: the built-in function "range()" returns a sequence ' - 'of\n' - 'integers suitable to emulate the effect of Pascal\'s "for i := a ' - 'to b\n' - 'do"; e.g., "range(3)" returns the list "[0, 1, 2]".\n' - '\n' - 'Note: There is a subtlety when the sequence is being modified by ' - 'the\n' - ' loop (this can only occur for mutable sequences, i.e. lists). ' - 'An\n' - ' internal counter is used to keep track of which item is used ' - 'next,\n' - ' and this is incremented on each iteration. When this counter ' - 'has\n' - ' reached the length of the sequence the loop terminates. This ' - 'means\n' - ' that if the suite deletes the current (or a previous) item ' - 'from the\n' - ' sequence, the next item will be skipped (since it gets the ' - 'index of\n' - ' the current item which has already been treated). Likewise, ' - 'if the\n' - ' suite inserts an item in the sequence before the current item, ' - 'the\n' - ' current item will be treated again the next time through the ' - 'loop.\n' - ' This can lead to nasty bugs that can be avoided by making a\n' - ' temporary copy using a slice of the whole sequence, e.g.,\n' - '\n' - ' for x in a[:]:\n' - ' if x < 0: a.remove(x)\n' - '\n' - '\n' - 'The "try" statement\n' - '===================\n' - '\n' - 'The "try" statement specifies exception handlers and/or cleanup ' - 'code\n' - 'for a group of statements:\n' - '\n' - ' try_stmt ::= try1_stmt | try2_stmt\n' - ' try1_stmt ::= "try" ":" suite\n' - ' ("except" [expression [("as" | ",") ' - 'identifier]] ":" suite)+\n' - ' ["else" ":" suite]\n' - ' ["finally" ":" suite]\n' - ' try2_stmt ::= "try" ":" suite\n' - ' "finally" ":" suite\n' - '\n' - 'Changed in version 2.5: In previous versions of Python,\n' - '"try"..."except"..."finally" did not work. "try"..."except" had ' - 'to be\n' - 'nested in "try"..."finally".\n' - '\n' - 'The "except" clause(s) specify one or more exception handlers. ' - 'When no\n' - 'exception occurs in the "try" clause, no exception handler is\n' - 'executed. When an exception occurs in the "try" suite, a search ' - 'for an\n' - 'exception handler is started. This search inspects the except ' - 'clauses\n' - 'in turn until one is found that matches the exception. An ' - 'expression-\n' - 'less except clause, if present, must be last; it matches any\n' - 'exception. For an except clause with an expression, that ' - 'expression\n' - 'is evaluated, and the clause matches the exception if the ' - 'resulting\n' - 'object is "compatible" with the exception. An object is ' - 'compatible\n' - 'with an exception if it is the class or a base class of the ' - 'exception\n' - 'object, or a tuple containing an item compatible with the ' - 'exception.\n' - '\n' - 'If no except clause matches the exception, the search for an ' - 'exception\n' - 'handler continues in the surrounding code and on the invocation ' - 'stack.\n' - '[1]\n' - '\n' - 'If the evaluation of an expression in the header of an except ' - 'clause\n' - 'raises an exception, the original search for a handler is ' - 'canceled and\n' - 'a search starts for the new exception in the surrounding code ' - 'and on\n' - 'the call stack (it is treated as if the entire "try" statement ' - 'raised\n' - 'the exception).\n' - '\n' - 'When a matching except clause is found, the exception is ' - 'assigned to\n' - 'the target specified in that except clause, if present, and the ' - 'except\n' - "clause's suite is executed. All except clauses must have an\n" - 'executable block. When the end of this block is reached, ' - 'execution\n' - 'continues normally after the entire try statement. (This means ' - 'that\n' - 'if two nested handlers exist for the same exception, and the ' - 'exception\n' - 'occurs in the try clause of the inner handler, the outer handler ' - 'will\n' - 'not handle the exception.)\n' - '\n' - "Before an except clause's suite is executed, details about the\n" - 'exception are assigned to three variables in the "sys" module:\n' - '"sys.exc_type" receives the object identifying the exception;\n' - '"sys.exc_value" receives the exception\'s parameter;\n' - '"sys.exc_traceback" receives a traceback object (see section ' - 'The\n' - 'standard type hierarchy) identifying the point in the program ' - 'where\n' - 'the exception occurred. These details are also available through ' - 'the\n' - '"sys.exc_info()" function, which returns a tuple "(exc_type,\n' - 'exc_value, exc_traceback)". Use of the corresponding variables ' - 'is\n' - 'deprecated in favor of this function, since their use is unsafe ' - 'in a\n' - 'threaded program. As of Python 1.5, the variables are restored ' - 'to\n' - 'their previous values (before the call) when returning from a ' - 'function\n' - 'that handled an exception.\n' - '\n' - 'The optional "else" clause is executed if and when control flows ' - 'off\n' - 'the end of the "try" clause. [2] Exceptions in the "else" clause ' - 'are\n' - 'not handled by the preceding "except" clauses.\n' - '\n' - 'If "finally" is present, it specifies a \'cleanup\' handler. ' - 'The "try"\n' - 'clause is executed, including any "except" and "else" clauses. ' - 'If an\n' - 'exception occurs in any of the clauses and is not handled, the\n' - 'exception is temporarily saved. The "finally" clause is ' - 'executed. If\n' - 'there is a saved exception, it is re-raised at the end of the\n' - '"finally" clause. If the "finally" clause raises another ' - 'exception or\n' - 'executes a "return" or "break" statement, the saved exception ' - 'is\n' - 'discarded:\n' - '\n' - ' >>> def f():\n' - ' ... try:\n' - ' ... 1/0\n' - ' ... finally:\n' - ' ... return 42\n' - ' ...\n' - ' >>> f()\n' - ' 42\n' - '\n' - 'The exception information is not available to the program ' - 'during\n' - 'execution of the "finally" clause.\n' - '\n' - 'When a "return", "break" or "continue" statement is executed in ' - 'the\n' - '"try" suite of a "try"..."finally" statement, the "finally" ' - 'clause is\n' - 'also executed \'on the way out.\' A "continue" statement is ' - 'illegal in\n' - 'the "finally" clause. (The reason is a problem with the current\n' - 'implementation --- this restriction may be lifted in the ' - 'future).\n' - '\n' - 'The return value of a function is determined by the last ' - '"return"\n' - 'statement executed. Since the "finally" clause always executes, ' - 'a\n' - '"return" statement executed in the "finally" clause will always ' - 'be the\n' - 'last one executed:\n' - '\n' - ' >>> def foo():\n' - ' ... try:\n' - " ... return 'try'\n" - ' ... finally:\n' - " ... return 'finally'\n" - ' ...\n' - ' >>> foo()\n' - " 'finally'\n" - '\n' - 'Additional information on exceptions can be found in section\n' - 'Exceptions, and information on using the "raise" statement to ' - 'generate\n' - 'exceptions may be found in section The raise statement.\n' - '\n' - '\n' - 'The "with" statement\n' - '====================\n' - '\n' - 'New in version 2.5.\n' - '\n' - 'The "with" statement is used to wrap the execution of a block ' - 'with\n' - 'methods defined by a context manager (see section With ' - 'Statement\n' - 'Context Managers). This allows common ' - '"try"..."except"..."finally"\n' - 'usage patterns to be encapsulated for convenient reuse.\n' - '\n' - ' with_stmt ::= "with" with_item ("," with_item)* ":" suite\n' - ' with_item ::= expression ["as" target]\n' - '\n' - 'The execution of the "with" statement with one "item" proceeds ' - 'as\n' - 'follows:\n' - '\n' - '1. The context expression (the expression given in the ' - '"with_item")\n' - ' is evaluated to obtain a context manager.\n' - '\n' - '2. The context manager\'s "__exit__()" is loaded for later use.\n' - '\n' - '3. The context manager\'s "__enter__()" method is invoked.\n' - '\n' - '4. If a target was included in the "with" statement, the return\n' - ' value from "__enter__()" is assigned to it.\n' - '\n' - ' Note: The "with" statement guarantees that if the ' - '"__enter__()"\n' - ' method returns without an error, then "__exit__()" will ' - 'always be\n' - ' called. Thus, if an error occurs during the assignment to ' - 'the\n' - ' target list, it will be treated the same as an error ' - 'occurring\n' - ' within the suite would be. See step 6 below.\n' - '\n' - '5. The suite is executed.\n' - '\n' - '6. The context manager\'s "__exit__()" method is invoked. If an\n' - ' exception caused the suite to be exited, its type, value, ' - 'and\n' - ' traceback are passed as arguments to "__exit__()". Otherwise, ' - 'three\n' - ' "None" arguments are supplied.\n' - '\n' - ' If the suite was exited due to an exception, and the return ' - 'value\n' - ' from the "__exit__()" method was false, the exception is ' - 'reraised.\n' - ' If the return value was true, the exception is suppressed, ' - 'and\n' - ' execution continues with the statement following the "with"\n' - ' statement.\n' - '\n' - ' If the suite was exited for any reason other than an ' - 'exception, the\n' - ' return value from "__exit__()" is ignored, and execution ' - 'proceeds\n' - ' at the normal location for the kind of exit that was taken.\n' - '\n' - 'With more than one item, the context managers are processed as ' - 'if\n' - 'multiple "with" statements were nested:\n' - '\n' - ' with A() as a, B() as b:\n' - ' suite\n' - '\n' - 'is equivalent to\n' - '\n' - ' with A() as a:\n' - ' with B() as b:\n' - ' suite\n' - '\n' - 'Note: In Python 2.5, the "with" statement is only allowed when ' - 'the\n' - ' "with_statement" feature has been enabled. It is always ' - 'enabled in\n' - ' Python 2.6.\n' - '\n' - 'Changed in version 2.7: Support for multiple context ' - 'expressions.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 343** - The "with" statement\n' - ' The specification, background, and examples for the Python ' - '"with"\n' - ' statement.\n' - '\n' - '\n' - 'Function definitions\n' - '====================\n' - '\n' - 'A function definition defines a user-defined function object ' - '(see\n' - 'section The standard type hierarchy):\n' - '\n' - ' decorated ::= decorators (classdef | funcdef)\n' - ' decorators ::= decorator+\n' - ' decorator ::= "@" dotted_name ["(" [argument_list [","]] ' - '")"] NEWLINE\n' - ' funcdef ::= "def" funcname "(" [parameter_list] ")" ' - '":" suite\n' - ' dotted_name ::= identifier ("." identifier)*\n' - ' parameter_list ::= (defparameter ",")*\n' - ' ( "*" identifier ["," "**" identifier]\n' - ' | "**" identifier\n' - ' | defparameter [","] )\n' - ' defparameter ::= parameter ["=" expression]\n' - ' sublist ::= parameter ("," parameter)* [","]\n' - ' parameter ::= identifier | "(" sublist ")"\n' - ' funcname ::= identifier\n' - '\n' - 'A function definition is an executable statement. Its execution ' - 'binds\n' - 'the function name in the current local namespace to a function ' - 'object\n' - '(a wrapper around the executable code for the function). This\n' - 'function object contains a reference to the current global ' - 'namespace\n' - 'as the global namespace to be used when the function is called.\n' - '\n' - 'The function definition does not execute the function body; this ' - 'gets\n' - 'executed only when the function is called. [3]\n' - '\n' - 'A function definition may be wrapped by one or more *decorator*\n' - 'expressions. Decorator expressions are evaluated when the ' - 'function is\n' - 'defined, in the scope that contains the function definition. ' - 'The\n' - 'result must be a callable, which is invoked with the function ' - 'object\n' - 'as the only argument. The returned value is bound to the ' - 'function name\n' - 'instead of the function object. Multiple decorators are applied ' - 'in\n' - 'nested fashion. For example, the following code:\n' - '\n' - ' @f1(arg)\n' - ' @f2\n' - ' def func(): pass\n' - '\n' - 'is equivalent to:\n' - '\n' - ' def func(): pass\n' - ' func = f1(arg)(f2(func))\n' - '\n' - 'When one or more top-level *parameters* have the form ' - '*parameter* "="\n' - '*expression*, the function is said to have "default parameter ' - 'values."\n' - 'For a parameter with a default value, the corresponding ' - '*argument* may\n' - "be omitted from a call, in which case the parameter's default " - 'value is\n' - 'substituted. If a parameter has a default value, all following\n' - 'parameters must also have a default value --- this is a ' - 'syntactic\n' - 'restriction that is not expressed by the grammar.\n' - '\n' - '**Default parameter values are evaluated when the function ' - 'definition\n' - 'is executed.** This means that the expression is evaluated ' - 'once, when\n' - 'the function is defined, and that the same "pre-computed" value ' - 'is\n' - 'used for each call. This is especially important to understand ' - 'when a\n' - 'default parameter is a mutable object, such as a list or a ' - 'dictionary:\n' - 'if the function modifies the object (e.g. by appending an item ' - 'to a\n' - 'list), the default value is in effect modified. This is ' - 'generally not\n' - 'what was intended. A way around this is to use "None" as the\n' - 'default, and explicitly test for it in the body of the function, ' - 'e.g.:\n' - '\n' - ' def whats_on_the_telly(penguin=None):\n' - ' if penguin is None:\n' - ' penguin = []\n' - ' penguin.append("property of the zoo")\n' - ' return penguin\n' - '\n' - 'Function call semantics are described in more detail in section ' - 'Calls.\n' - 'A function call always assigns values to all parameters ' - 'mentioned in\n' - 'the parameter list, either from position arguments, from ' - 'keyword\n' - 'arguments, or from default values. If the form ""*identifier"" ' - 'is\n' - 'present, it is initialized to a tuple receiving any excess ' - 'positional\n' - 'parameters, defaulting to the empty tuple. If the form\n' - '""**identifier"" is present, it is initialized to a new ' - 'dictionary\n' - 'receiving any excess keyword arguments, defaulting to a new ' - 'empty\n' - 'dictionary.\n' - '\n' - 'It is also possible to create anonymous functions (functions not ' - 'bound\n' - 'to a name), for immediate use in expressions. This uses lambda\n' - 'expressions, described in section Lambdas. Note that the ' - 'lambda\n' - 'expression is merely a shorthand for a simplified function ' - 'definition;\n' - 'a function defined in a ""def"" statement can be passed around ' - 'or\n' - 'assigned to another name just like a function defined by a ' - 'lambda\n' - 'expression. The ""def"" form is actually more powerful since ' - 'it\n' - 'allows the execution of multiple statements.\n' - '\n' - "**Programmer's note:** Functions are first-class objects. A " - '""def""\n' - 'form executed inside a function definition defines a local ' - 'function\n' - 'that can be returned or passed around. Free variables used in ' - 'the\n' - 'nested function can access the local variables of the function\n' - 'containing the def. See section Naming and binding for ' - 'details.\n' - '\n' - '\n' - 'Class definitions\n' - '=================\n' - '\n' - 'A class definition defines a class object (see section The ' - 'standard\n' - 'type hierarchy):\n' - '\n' - ' classdef ::= "class" classname [inheritance] ":" suite\n' - ' inheritance ::= "(" [expression_list] ")"\n' - ' classname ::= identifier\n' - '\n' - 'A class definition is an executable statement. It first ' - 'evaluates the\n' - 'inheritance list, if present. Each item in the inheritance ' - 'list\n' - 'should evaluate to a class object or class type which allows\n' - "subclassing. The class's suite is then executed in a new " - 'execution\n' - 'frame (see section Naming and binding), using a newly created ' - 'local\n' - 'namespace and the original global namespace. (Usually, the ' - 'suite\n' - "contains only function definitions.) When the class's suite " - 'finishes\n' - 'execution, its execution frame is discarded but its local ' - 'namespace is\n' - 'saved. [4] A class object is then created using the inheritance ' - 'list\n' - 'for the base classes and the saved local namespace for the ' - 'attribute\n' - 'dictionary. The class name is bound to this class object in ' - 'the\n' - 'original local namespace.\n' - '\n' - "**Programmer's note:** Variables defined in the class definition " - 'are\n' - 'class variables; they are shared by all instances. To create ' - 'instance\n' - 'variables, they can be set in a method with "self.name = ' - 'value". Both\n' - 'class and instance variables are accessible through the ' - 'notation\n' - '""self.name"", and an instance variable hides a class variable ' - 'with\n' - 'the same name when accessed in this way. Class variables can be ' - 'used\n' - 'as defaults for instance variables, but using mutable values ' - 'there can\n' - 'lead to unexpected results. For *new-style class*es, ' - 'descriptors can\n' - 'be used to create instance variables with different ' - 'implementation\n' - 'details.\n' - '\n' - 'Class definitions, like function definitions, may be wrapped by ' - 'one or\n' - 'more *decorator* expressions. The evaluation rules for the ' - 'decorator\n' - 'expressions are the same as for functions. The result must be a ' - 'class\n' - 'object, which is then bound to the class name.\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] The exception is propagated to the invocation stack unless\n' - ' there is a "finally" clause which happens to raise another\n' - ' exception. That new exception causes the old one to be ' - 'lost.\n' - '\n' - '[2] Currently, control "flows off the end" except in the case ' - 'of\n' - ' an exception or the execution of a "return", "continue", or\n' - ' "break" statement.\n' - '\n' - '[3] A string literal appearing as the first statement in the\n' - ' function body is transformed into the function\'s "__doc__"\n' - " attribute and therefore the function's *docstring*.\n" - '\n' - '[4] A string literal appearing as the first statement in the ' - 'class\n' - ' body is transformed into the namespace\'s "__doc__" item ' - 'and\n' - " therefore the class's *docstring*.\n", - 'context-managers': '\n' - 'With Statement Context Managers\n' - '*******************************\n' - '\n' - 'New in version 2.5.\n' - '\n' - 'A *context manager* is an object that defines the ' - 'runtime context to\n' - 'be established when executing a "with" statement. The ' - 'context manager\n' - 'handles the entry into, and the exit from, the desired ' - 'runtime context\n' - 'for the execution of the block of code. Context ' - 'managers are normally\n' - 'invoked using the "with" statement (described in section ' - 'The with\n' - 'statement), but can also be used by directly invoking ' - 'their methods.\n' - '\n' - 'Typical uses of context managers include saving and ' - 'restoring various\n' - 'kinds of global state, locking and unlocking resources, ' - 'closing opened\n' - 'files, etc.\n' - '\n' - 'For more information on context managers, see Context ' - 'Manager Types.\n' - '\n' - 'object.__enter__(self)\n' - '\n' - ' Enter the runtime context related to this object. The ' - '"with"\n' - " statement will bind this method's return value to the " - 'target(s)\n' - ' specified in the "as" clause of the statement, if ' - 'any.\n' - '\n' - 'object.__exit__(self, exc_type, exc_value, traceback)\n' - '\n' - ' Exit the runtime context related to this object. The ' - 'parameters\n' - ' describe the exception that caused the context to be ' - 'exited. If the\n' - ' context was exited without an exception, all three ' - 'arguments will\n' - ' be "None".\n' - '\n' - ' If an exception is supplied, and the method wishes to ' - 'suppress the\n' - ' exception (i.e., prevent it from being propagated), ' - 'it should\n' - ' return a true value. Otherwise, the exception will be ' - 'processed\n' - ' normally upon exit from this method.\n' - '\n' - ' Note that "__exit__()" methods should not reraise the ' - 'passed-in\n' - " exception; this is the caller's responsibility.\n" - '\n' - 'See also:\n' - '\n' - ' **PEP 343** - The "with" statement\n' - ' The specification, background, and examples for the ' - 'Python "with"\n' - ' statement.\n', - 'continue': '\n' - 'The "continue" statement\n' - '************************\n' - '\n' - ' continue_stmt ::= "continue"\n' - '\n' - '"continue" may only occur syntactically nested in a "for" or ' - '"while"\n' - 'loop, but not nested in a function or class definition or ' - '"finally"\n' - 'clause within that loop. It continues with the next cycle of ' - 'the\n' - 'nearest enclosing loop.\n' - '\n' - 'When "continue" passes control out of a "try" statement with a\n' - '"finally" clause, that "finally" clause is executed before ' - 'really\n' - 'starting the next loop cycle.\n', - 'conversions': '\n' - 'Arithmetic conversions\n' - '**********************\n' - '\n' - 'When a description of an arithmetic operator below uses the ' - 'phrase\n' - '"the numeric arguments are converted to a common type," the ' - 'arguments\n' - 'are coerced using the coercion rules listed at Coercion ' - 'rules. If\n' - 'both arguments are standard numeric types, the following ' - 'coercions are\n' - 'applied:\n' - '\n' - '* If either argument is a complex number, the other is ' - 'converted to\n' - ' complex;\n' - '\n' - '* otherwise, if either argument is a floating point number, ' - 'the\n' - ' other is converted to floating point;\n' - '\n' - '* otherwise, if either argument is a long integer, the other ' - 'is\n' - ' converted to long integer;\n' - '\n' - '* otherwise, both must be plain integers and no conversion ' - 'is\n' - ' necessary.\n' - '\n' - 'Some additional rules apply for certain operators (e.g., a ' - 'string left\n' - "argument to the '%' operator). Extensions can define their " - 'own\n' - 'coercions.\n', - 'customization': '\n' - 'Basic customization\n' - '*******************\n' - '\n' - 'object.__new__(cls[, ...])\n' - '\n' - ' Called to create a new instance of class *cls*. ' - '"__new__()" is a\n' - ' static method (special-cased so you need not declare it ' - 'as such)\n' - ' that takes the class of which an instance was requested ' - 'as its\n' - ' first argument. The remaining arguments are those ' - 'passed to the\n' - ' object constructor expression (the call to the class). ' - 'The return\n' - ' value of "__new__()" should be the new object instance ' - '(usually an\n' - ' instance of *cls*).\n' - '\n' - ' Typical implementations create a new instance of the ' - 'class by\n' - ' invoking the superclass\'s "__new__()" method using\n' - ' "super(currentclass, cls).__new__(cls[, ...])" with ' - 'appropriate\n' - ' arguments and then modifying the newly-created instance ' - 'as\n' - ' necessary before returning it.\n' - '\n' - ' If "__new__()" returns an instance of *cls*, then the ' - 'new\n' - ' instance\'s "__init__()" method will be invoked like\n' - ' "__init__(self[, ...])", where *self* is the new ' - 'instance and the\n' - ' remaining arguments are the same as were passed to ' - '"__new__()".\n' - '\n' - ' If "__new__()" does not return an instance of *cls*, ' - 'then the new\n' - ' instance\'s "__init__()" method will not be invoked.\n' - '\n' - ' "__new__()" is intended mainly to allow subclasses of ' - 'immutable\n' - ' types (like int, str, or tuple) to customize instance ' - 'creation. It\n' - ' is also commonly overridden in custom metaclasses in ' - 'order to\n' - ' customize class creation.\n' - '\n' - 'object.__init__(self[, ...])\n' - '\n' - ' Called after the instance has been created (by ' - '"__new__()"), but\n' - ' before it is returned to the caller. The arguments are ' - 'those\n' - ' passed to the class constructor expression. If a base ' - 'class has an\n' - ' "__init__()" method, the derived class\'s "__init__()" ' - 'method, if\n' - ' any, must explicitly call it to ensure proper ' - 'initialization of the\n' - ' base class part of the instance; for example:\n' - ' "BaseClass.__init__(self, [args...])".\n' - '\n' - ' Because "__new__()" and "__init__()" work together in ' - 'constructing\n' - ' objects ("__new__()" to create it, and "__init__()" to ' - 'customise\n' - ' it), no non-"None" value may be returned by ' - '"__init__()"; doing so\n' - ' will cause a "TypeError" to be raised at runtime.\n' - '\n' - 'object.__del__(self)\n' - '\n' - ' Called when the instance is about to be destroyed. This ' - 'is also\n' - ' called a destructor. If a base class has a "__del__()" ' - 'method, the\n' - ' derived class\'s "__del__()" method, if any, must ' - 'explicitly call it\n' - ' to ensure proper deletion of the base class part of the ' - 'instance.\n' - ' Note that it is possible (though not recommended!) for ' - 'the\n' - ' "__del__()" method to postpone destruction of the ' - 'instance by\n' - ' creating a new reference to it. It may then be called ' - 'at a later\n' - ' time when this new reference is deleted. It is not ' - 'guaranteed that\n' - ' "__del__()" methods are called for objects that still ' - 'exist when\n' - ' the interpreter exits.\n' - '\n' - ' Note: "del x" doesn\'t directly call "x.__del__()" --- ' - 'the former\n' - ' decrements the reference count for "x" by one, and the ' - 'latter is\n' - ' only called when "x"\'s reference count reaches zero. ' - 'Some common\n' - ' situations that may prevent the reference count of an ' - 'object from\n' - ' going to zero include: circular references between ' - 'objects (e.g.,\n' - ' a doubly-linked list or a tree data structure with ' - 'parent and\n' - ' child pointers); a reference to the object on the ' - 'stack frame of\n' - ' a function that caught an exception (the traceback ' - 'stored in\n' - ' "sys.exc_traceback" keeps the stack frame alive); or a ' - 'reference\n' - ' to the object on the stack frame that raised an ' - 'unhandled\n' - ' exception in interactive mode (the traceback stored ' - 'in\n' - ' "sys.last_traceback" keeps the stack frame alive). ' - 'The first\n' - ' situation can only be remedied by explicitly breaking ' - 'the cycles;\n' - ' the latter two situations can be resolved by storing ' - '"None" in\n' - ' "sys.exc_traceback" or "sys.last_traceback". Circular ' - 'references\n' - ' which are garbage are detected when the option cycle ' - 'detector is\n' - " enabled (it's on by default), but can only be cleaned " - 'up if there\n' - ' are no Python-level "__del__()" methods involved. ' - 'Refer to the\n' - ' documentation for the "gc" module for more information ' - 'about how\n' - ' "__del__()" methods are handled by the cycle ' - 'detector,\n' - ' particularly the description of the "garbage" value.\n' - '\n' - ' Warning: Due to the precarious circumstances under ' - 'which\n' - ' "__del__()" methods are invoked, exceptions that occur ' - 'during\n' - ' their execution are ignored, and a warning is printed ' - 'to\n' - ' "sys.stderr" instead. Also, when "__del__()" is ' - 'invoked in\n' - ' response to a module being deleted (e.g., when ' - 'execution of the\n' - ' program is done), other globals referenced by the ' - '"__del__()"\n' - ' method may already have been deleted or in the process ' - 'of being\n' - ' torn down (e.g. the import machinery shutting down). ' - 'For this\n' - ' reason, "__del__()" methods should do the absolute ' - 'minimum needed\n' - ' to maintain external invariants. Starting with ' - 'version 1.5,\n' - ' Python guarantees that globals whose name begins with ' - 'a single\n' - ' underscore are deleted from their module before other ' - 'globals are\n' - ' deleted; if no other references to such globals exist, ' - 'this may\n' - ' help in assuring that imported modules are still ' - 'available at the\n' - ' time when the "__del__()" method is called.\n' - '\n' - ' See also the "-R" command-line option.\n' - '\n' - 'object.__repr__(self)\n' - '\n' - ' Called by the "repr()" built-in function and by string ' - 'conversions\n' - ' (reverse quotes) to compute the "official" string ' - 'representation of\n' - ' an object. If at all possible, this should look like a ' - 'valid\n' - ' Python expression that could be used to recreate an ' - 'object with the\n' - ' same value (given an appropriate environment). If this ' - 'is not\n' - ' possible, a string of the form "<...some useful ' - 'description...>"\n' - ' should be returned. The return value must be a string ' - 'object. If a\n' - ' class defines "__repr__()" but not "__str__()", then ' - '"__repr__()"\n' - ' is also used when an "informal" string representation of ' - 'instances\n' - ' of that class is required.\n' - '\n' - ' This is typically used for debugging, so it is important ' - 'that the\n' - ' representation is information-rich and unambiguous.\n' - '\n' - 'object.__str__(self)\n' - '\n' - ' Called by the "str()" built-in function and by the ' - '"print"\n' - ' statement to compute the "informal" string ' - 'representation of an\n' - ' object. This differs from "__repr__()" in that it does ' - 'not have to\n' - ' be a valid Python expression: a more convenient or ' - 'concise\n' - ' representation may be used instead. The return value ' - 'must be a\n' - ' string object.\n' - '\n' - 'object.__lt__(self, other)\n' - 'object.__le__(self, other)\n' - 'object.__eq__(self, other)\n' - 'object.__ne__(self, other)\n' - 'object.__gt__(self, other)\n' - 'object.__ge__(self, other)\n' - '\n' - ' New in version 2.1.\n' - '\n' - ' These are the so-called "rich comparison" methods, and ' - 'are called\n' - ' for comparison operators in preference to "__cmp__()" ' - 'below. The\n' - ' correspondence between operator symbols and method names ' - 'is as\n' - ' follows: "x<y" calls "x.__lt__(y)", "x<=y" calls ' - '"x.__le__(y)",\n' - ' "x==y" calls "x.__eq__(y)", "x!=y" and "x<>y" call ' - '"x.__ne__(y)",\n' - ' "x>y" calls "x.__gt__(y)", and "x>=y" calls ' - '"x.__ge__(y)".\n' - '\n' - ' A rich comparison method may return the singleton ' - '"NotImplemented"\n' - ' if it does not implement the operation for a given pair ' - 'of\n' - ' arguments. By convention, "False" and "True" are ' - 'returned for a\n' - ' successful comparison. However, these methods can return ' - 'any value,\n' - ' so if the comparison operator is used in a Boolean ' - 'context (e.g.,\n' - ' in the condition of an "if" statement), Python will call ' - '"bool()"\n' - ' on the value to determine if the result is true or ' - 'false.\n' - '\n' - ' There are no implied relationships among the comparison ' - 'operators.\n' - ' The truth of "x==y" does not imply that "x!=y" is ' - 'false.\n' - ' Accordingly, when defining "__eq__()", one should also ' - 'define\n' - ' "__ne__()" so that the operators will behave as ' - 'expected. See the\n' - ' paragraph on "__hash__()" for some important notes on ' - 'creating\n' - ' *hashable* objects which support custom comparison ' - 'operations and\n' - ' are usable as dictionary keys.\n' - '\n' - ' There are no swapped-argument versions of these methods ' - '(to be used\n' - ' when the left argument does not support the operation ' - 'but the right\n' - ' argument does); rather, "__lt__()" and "__gt__()" are ' - "each other's\n" - ' reflection, "__le__()" and "__ge__()" are each other\'s ' - 'reflection,\n' - ' and "__eq__()" and "__ne__()" are their own reflection.\n' - '\n' - ' Arguments to rich comparison methods are never coerced.\n' - '\n' - ' To automatically generate ordering operations from a ' - 'single root\n' - ' operation, see "functools.total_ordering()".\n' - '\n' - 'object.__cmp__(self, other)\n' - '\n' - ' Called by comparison operations if rich comparison (see ' - 'above) is\n' - ' not defined. Should return a negative integer if "self ' - '< other",\n' - ' zero if "self == other", a positive integer if "self > ' - 'other". If\n' - ' no "__cmp__()", "__eq__()" or "__ne__()" operation is ' - 'defined,\n' - ' class instances are compared by object identity ' - '("address"). See\n' - ' also the description of "__hash__()" for some important ' - 'notes on\n' - ' creating *hashable* objects which support custom ' - 'comparison\n' - ' operations and are usable as dictionary keys. (Note: ' - 'the\n' - ' restriction that exceptions are not propagated by ' - '"__cmp__()" has\n' - ' been removed since Python 1.5.)\n' - '\n' - 'object.__rcmp__(self, other)\n' - '\n' - ' Changed in version 2.1: No longer supported.\n' - '\n' - 'object.__hash__(self)\n' - '\n' - ' Called by built-in function "hash()" and for operations ' - 'on members\n' - ' of hashed collections including "set", "frozenset", and ' - '"dict".\n' - ' "__hash__()" should return an integer. The only ' - 'required property\n' - ' is that objects which compare equal have the same hash ' - 'value; it is\n' - ' advised to mix together the hash values of the ' - 'components of the\n' - ' object that also play a part in comparison of objects by ' - 'packing\n' - ' them into a tuple and hashing the tuple. Example:\n' - '\n' - ' def __hash__(self):\n' - ' return hash((self.name, self.nick, self.color))\n' - '\n' - ' If a class does not define a "__cmp__()" or "__eq__()" ' - 'method it\n' - ' should not define a "__hash__()" operation either; if it ' - 'defines\n' - ' "__cmp__()" or "__eq__()" but not "__hash__()", its ' - 'instances will\n' - ' not be usable in hashed collections. If a class defines ' - 'mutable\n' - ' objects and implements a "__cmp__()" or "__eq__()" ' - 'method, it\n' - ' should not implement "__hash__()", since hashable ' - 'collection\n' - " implementations require that an object's hash value is " - 'immutable\n' - " (if the object's hash value changes, it will be in the " - 'wrong hash\n' - ' bucket).\n' - '\n' - ' User-defined classes have "__cmp__()" and "__hash__()" ' - 'methods by\n' - ' default; with them, all objects compare unequal (except ' - 'with\n' - ' themselves) and "x.__hash__()" returns a result derived ' - 'from\n' - ' "id(x)".\n' - '\n' - ' Classes which inherit a "__hash__()" method from a ' - 'parent class but\n' - ' change the meaning of "__cmp__()" or "__eq__()" such ' - 'that the hash\n' - ' value returned is no longer appropriate (e.g. by ' - 'switching to a\n' - ' value-based concept of equality instead of the default ' - 'identity\n' - ' based equality) can explicitly flag themselves as being ' - 'unhashable\n' - ' by setting "__hash__ = None" in the class definition. ' - 'Doing so\n' - ' means that not only will instances of the class raise ' - 'an\n' - ' appropriate "TypeError" when a program attempts to ' - 'retrieve their\n' - ' hash value, but they will also be correctly identified ' - 'as\n' - ' unhashable when checking "isinstance(obj, ' - 'collections.Hashable)"\n' - ' (unlike classes which define their own "__hash__()" to ' - 'explicitly\n' - ' raise "TypeError").\n' - '\n' - ' Changed in version 2.5: "__hash__()" may now also return ' - 'a long\n' - ' integer object; the 32-bit integer is then derived from ' - 'the hash of\n' - ' that object.\n' - '\n' - ' Changed in version 2.6: "__hash__" may now be set to ' - '"None" to\n' - ' explicitly flag instances of a class as unhashable.\n' - '\n' - 'object.__nonzero__(self)\n' - '\n' - ' Called to implement truth value testing and the built-in ' - 'operation\n' - ' "bool()"; should return "False" or "True", or their ' - 'integer\n' - ' equivalents "0" or "1". When this method is not ' - 'defined,\n' - ' "__len__()" is called, if it is defined, and the object ' - 'is\n' - ' considered true if its result is nonzero. If a class ' - 'defines\n' - ' neither "__len__()" nor "__nonzero__()", all its ' - 'instances are\n' - ' considered true.\n' - '\n' - 'object.__unicode__(self)\n' - '\n' - ' Called to implement "unicode()" built-in; should return ' - 'a Unicode\n' - ' object. When this method is not defined, string ' - 'conversion is\n' - ' attempted, and the result of string conversion is ' - 'converted to\n' - ' Unicode using the system default encoding.\n', - 'debugger': '\n' - '"pdb" --- The Python Debugger\n' - '*****************************\n' - '\n' - '**Source code:** Lib/pdb.py\n' - '\n' - '======================================================================\n' - '\n' - 'The module "pdb" defines an interactive source code debugger ' - 'for\n' - 'Python programs. It supports setting (conditional) breakpoints ' - 'and\n' - 'single stepping at the source line level, inspection of stack ' - 'frames,\n' - 'source code listing, and evaluation of arbitrary Python code in ' - 'the\n' - 'context of any stack frame. It also supports post-mortem ' - 'debugging\n' - 'and can be called under program control.\n' - '\n' - 'The debugger is extensible --- it is actually defined as the ' - 'class\n' - '"Pdb". This is currently undocumented but easily understood by ' - 'reading\n' - 'the source. The extension interface uses the modules "bdb" and ' - '"cmd".\n' - '\n' - 'The debugger\'s prompt is "(Pdb)". Typical usage to run a ' - 'program under\n' - 'control of the debugger is:\n' - '\n' - ' >>> import pdb\n' - ' >>> import mymodule\n' - " >>> pdb.run('mymodule.test()')\n" - ' > <string>(0)?()\n' - ' (Pdb) continue\n' - ' > <string>(1)?()\n' - ' (Pdb) continue\n' - " NameError: 'spam'\n" - ' > <string>(1)?()\n' - ' (Pdb)\n' - '\n' - '"pdb.py" can also be invoked as a script to debug other ' - 'scripts. For\n' - 'example:\n' - '\n' - ' python -m pdb myscript.py\n' - '\n' - 'When invoked as a script, pdb will automatically enter ' - 'post-mortem\n' - 'debugging if the program being debugged exits abnormally. After ' - 'post-\n' - 'mortem debugging (or after normal exit of the program), pdb ' - 'will\n' - "restart the program. Automatic restarting preserves pdb's state " - '(such\n' - 'as breakpoints) and in most cases is more useful than quitting ' - 'the\n' - "debugger upon program's exit.\n" - '\n' - 'New in version 2.4: Restarting post-mortem behavior added.\n' - '\n' - 'The typical usage to break into the debugger from a running ' - 'program is\n' - 'to insert\n' - '\n' - ' import pdb; pdb.set_trace()\n' - '\n' - 'at the location you want to break into the debugger. You can ' - 'then\n' - 'step through the code following this statement, and continue ' - 'running\n' - 'without the debugger using the "c" command.\n' - '\n' - 'The typical usage to inspect a crashed program is:\n' - '\n' - ' >>> import pdb\n' - ' >>> import mymodule\n' - ' >>> mymodule.test()\n' - ' Traceback (most recent call last):\n' - ' File "<stdin>", line 1, in <module>\n' - ' File "./mymodule.py", line 4, in test\n' - ' test2()\n' - ' File "./mymodule.py", line 3, in test2\n' - ' print spam\n' - ' NameError: spam\n' - ' >>> pdb.pm()\n' - ' > ./mymodule.py(3)test2()\n' - ' -> print spam\n' - ' (Pdb)\n' - '\n' - 'The module defines the following functions; each enters the ' - 'debugger\n' - 'in a slightly different way:\n' - '\n' - 'pdb.run(statement[, globals[, locals]])\n' - '\n' - ' Execute the *statement* (given as a string) under debugger ' - 'control.\n' - ' The debugger prompt appears before any code is executed; you ' - 'can\n' - ' set breakpoints and type "continue", or you can step through ' - 'the\n' - ' statement using "step" or "next" (all these commands are ' - 'explained\n' - ' below). The optional *globals* and *locals* arguments ' - 'specify the\n' - ' environment in which the code is executed; by default the\n' - ' dictionary of the module "__main__" is used. (See the ' - 'explanation\n' - ' of the "exec" statement or the "eval()" built-in function.)\n' - '\n' - 'pdb.runeval(expression[, globals[, locals]])\n' - '\n' - ' Evaluate the *expression* (given as a string) under debugger\n' - ' control. When "runeval()" returns, it returns the value of ' - 'the\n' - ' expression. Otherwise this function is similar to "run()".\n' - '\n' - 'pdb.runcall(function[, argument, ...])\n' - '\n' - ' Call the *function* (a function or method object, not a ' - 'string)\n' - ' with the given arguments. When "runcall()" returns, it ' - 'returns\n' - ' whatever the function call returned. The debugger prompt ' - 'appears\n' - ' as soon as the function is entered.\n' - '\n' - 'pdb.set_trace()\n' - '\n' - ' Enter the debugger at the calling stack frame. This is ' - 'useful to\n' - ' hard-code a breakpoint at a given point in a program, even if ' - 'the\n' - ' code is not otherwise being debugged (e.g. when an assertion\n' - ' fails).\n' - '\n' - 'pdb.post_mortem([traceback])\n' - '\n' - ' Enter post-mortem debugging of the given *traceback* object. ' - 'If no\n' - ' *traceback* is given, it uses the one of the exception that ' - 'is\n' - ' currently being handled (an exception must be being handled ' - 'if the\n' - ' default is to be used).\n' - '\n' - 'pdb.pm()\n' - '\n' - ' Enter post-mortem debugging of the traceback found in\n' - ' "sys.last_traceback".\n' - '\n' - 'The "run*" functions and "set_trace()" are aliases for ' - 'instantiating\n' - 'the "Pdb" class and calling the method of the same name. If you ' - 'want\n' - 'to access further features, you have to do this yourself:\n' - '\n' - "class pdb.Pdb(completekey='tab', stdin=None, stdout=None, " - 'skip=None)\n' - '\n' - ' "Pdb" is the debugger class.\n' - '\n' - ' The *completekey*, *stdin* and *stdout* arguments are passed ' - 'to the\n' - ' underlying "cmd.Cmd" class; see the description there.\n' - '\n' - ' The *skip* argument, if given, must be an iterable of ' - 'glob-style\n' - ' module name patterns. The debugger will not step into frames ' - 'that\n' - ' originate in a module that matches one of these patterns. ' - '[1]\n' - '\n' - ' Example call to enable tracing with *skip*:\n' - '\n' - " import pdb; pdb.Pdb(skip=['django.*']).set_trace()\n" - '\n' - ' New in version 2.7: The *skip* argument.\n' - '\n' - ' run(statement[, globals[, locals]])\n' - ' runeval(expression[, globals[, locals]])\n' - ' runcall(function[, argument, ...])\n' - ' set_trace()\n' - '\n' - ' See the documentation for the functions explained above.\n', - 'del': '\n' - 'The "del" statement\n' - '*******************\n' - '\n' - ' del_stmt ::= "del" target_list\n' - '\n' - 'Deletion is recursively defined very similar to the way assignment ' - 'is\n' - 'defined. Rather than spelling it out in full details, here are some\n' - 'hints.\n' - '\n' - 'Deletion of a target list recursively deletes each target, from left\n' - 'to right.\n' - '\n' - 'Deletion of a name removes the binding of that name from the local ' - 'or\n' - 'global namespace, depending on whether the name occurs in a "global"\n' - 'statement in the same code block. If the name is unbound, a\n' - '"NameError" exception will be raised.\n' - '\n' - 'It is illegal to delete a name from the local namespace if it occurs\n' - 'as a free variable in a nested block.\n' - '\n' - 'Deletion of attribute references, subscriptions and slicings is ' - 'passed\n' - 'to the primary object involved; deletion of a slicing is in general\n' - 'equivalent to assignment of an empty slice of the right type (but ' - 'even\n' - 'this is determined by the sliced object).\n', - 'dict': '\n' - 'Dictionary displays\n' - '*******************\n' - '\n' - 'A dictionary display is a possibly empty series of key/datum pairs\n' - 'enclosed in curly braces:\n' - '\n' - ' dict_display ::= "{" [key_datum_list | dict_comprehension] ' - '"}"\n' - ' key_datum_list ::= key_datum ("," key_datum)* [","]\n' - ' key_datum ::= expression ":" expression\n' - ' dict_comprehension ::= expression ":" expression comp_for\n' - '\n' - 'A dictionary display yields a new dictionary object.\n' - '\n' - 'If a comma-separated sequence of key/datum pairs is given, they are\n' - 'evaluated from left to right to define the entries of the ' - 'dictionary:\n' - 'each key object is used as a key into the dictionary to store the\n' - 'corresponding datum. This means that you can specify the same key\n' - "multiple times in the key/datum list, and the final dictionary's " - 'value\n' - 'for that key will be the last one given.\n' - '\n' - 'A dict comprehension, in contrast to list and set comprehensions,\n' - 'needs two expressions separated with a colon followed by the usual\n' - '"for" and "if" clauses. When the comprehension is run, the ' - 'resulting\n' - 'key and value elements are inserted in the new dictionary in the ' - 'order\n' - 'they are produced.\n' - '\n' - 'Restrictions on the types of the key values are listed earlier in\n' - 'section The standard type hierarchy. (To summarize, the key type\n' - 'should be *hashable*, which excludes all mutable objects.) Clashes\n' - 'between duplicate keys are not detected; the last datum (textually\n' - 'rightmost in the display) stored for a given key value prevails.\n', - 'dynamic-features': '\n' - 'Interaction with dynamic features\n' - '*********************************\n' - '\n' - 'There are several cases where Python statements are ' - 'illegal when used\n' - 'in conjunction with nested scopes that contain free ' - 'variables.\n' - '\n' - 'If a variable is referenced in an enclosing scope, it is ' - 'illegal to\n' - 'delete the name. An error will be reported at compile ' - 'time.\n' - '\n' - 'If the wild card form of import --- "import *" --- is ' - 'used in a\n' - 'function and the function contains or is a nested block ' - 'with free\n' - 'variables, the compiler will raise a "SyntaxError".\n' - '\n' - 'If "exec" is used in a function and the function ' - 'contains or is a\n' - 'nested block with free variables, the compiler will ' - 'raise a\n' - '"SyntaxError" unless the exec explicitly specifies the ' - 'local namespace\n' - 'for the "exec". (In other words, "exec obj" would be ' - 'illegal, but\n' - '"exec obj in ns" would be legal.)\n' - '\n' - 'The "eval()", "execfile()", and "input()" functions and ' - 'the "exec"\n' - 'statement do not have access to the full environment for ' - 'resolving\n' - 'names. Names may be resolved in the local and global ' - 'namespaces of\n' - 'the caller. Free variables are not resolved in the ' - 'nearest enclosing\n' - 'namespace, but in the global namespace. [1] The "exec" ' - 'statement and\n' - 'the "eval()" and "execfile()" functions have optional ' - 'arguments to\n' - 'override the global and local namespace. If only one ' - 'namespace is\n' - 'specified, it is used for both.\n', - 'else': '\n' - 'The "if" statement\n' - '******************\n' - '\n' - 'The "if" statement is used for conditional execution:\n' - '\n' - ' if_stmt ::= "if" expression ":" suite\n' - ' ( "elif" expression ":" suite )*\n' - ' ["else" ":" suite]\n' - '\n' - 'It selects exactly one of the suites by evaluating the expressions ' - 'one\n' - 'by one until one is found to be true (see section Boolean ' - 'operations\n' - 'for the definition of true and false); then that suite is executed\n' - '(and no other part of the "if" statement is executed or evaluated).\n' - 'If all expressions are false, the suite of the "else" clause, if\n' - 'present, is executed.\n', - 'exceptions': '\n' - 'Exceptions\n' - '**********\n' - '\n' - 'Exceptions are a means of breaking out of the normal flow of ' - 'control\n' - 'of a code block in order to handle errors or other ' - 'exceptional\n' - 'conditions. An exception is *raised* at the point where the ' - 'error is\n' - 'detected; it may be *handled* by the surrounding code block or ' - 'by any\n' - 'code block that directly or indirectly invoked the code block ' - 'where\n' - 'the error occurred.\n' - '\n' - 'The Python interpreter raises an exception when it detects a ' - 'run-time\n' - 'error (such as division by zero). A Python program can also\n' - 'explicitly raise an exception with the "raise" statement. ' - 'Exception\n' - 'handlers are specified with the "try" ... "except" statement. ' - 'The\n' - '"finally" clause of such a statement can be used to specify ' - 'cleanup\n' - 'code which does not handle the exception, but is executed ' - 'whether an\n' - 'exception occurred or not in the preceding code.\n' - '\n' - 'Python uses the "termination" model of error handling: an ' - 'exception\n' - 'handler can find out what happened and continue execution at ' - 'an outer\n' - 'level, but it cannot repair the cause of the error and retry ' - 'the\n' - 'failing operation (except by re-entering the offending piece ' - 'of code\n' - 'from the top).\n' - '\n' - 'When an exception is not handled at all, the interpreter ' - 'terminates\n' - 'execution of the program, or returns to its interactive main ' - 'loop. In\n' - 'either case, it prints a stack backtrace, except when the ' - 'exception is\n' - '"SystemExit".\n' - '\n' - 'Exceptions are identified by class instances. The "except" ' - 'clause is\n' - 'selected depending on the class of the instance: it must ' - 'reference the\n' - 'class of the instance or a base class thereof. The instance ' - 'can be\n' - 'received by the handler and can carry additional information ' - 'about the\n' - 'exceptional condition.\n' - '\n' - 'Exceptions can also be identified by strings, in which case ' - 'the\n' - '"except" clause is selected by object identity. An arbitrary ' - 'value\n' - 'can be raised along with the identifying string which can be ' - 'passed to\n' - 'the handler.\n' - '\n' - 'Note: Messages to exceptions are not part of the Python API. ' - 'Their\n' - ' contents may change from one version of Python to the next ' - 'without\n' - ' warning and should not be relied on by code which will run ' - 'under\n' - ' multiple versions of the interpreter.\n' - '\n' - 'See also the description of the "try" statement in section The ' - 'try\n' - 'statement and "raise" statement in section The raise ' - 'statement.\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] This limitation occurs because the code that is executed ' - 'by\n' - ' these operations is not available at the time the module ' - 'is\n' - ' compiled.\n', - 'exec': '\n' - 'The "exec" statement\n' - '********************\n' - '\n' - ' exec_stmt ::= "exec" or_expr ["in" expression ["," expression]]\n' - '\n' - 'This statement supports dynamic execution of Python code. The ' - 'first\n' - 'expression should evaluate to either a Unicode string, a *Latin-1*\n' - 'encoded string, an open file object, a code object, or a tuple. If ' - 'it\n' - 'is a string, the string is parsed as a suite of Python statements\n' - 'which is then executed (unless a syntax error occurs). [1] If it is ' - 'an\n' - 'open file, the file is parsed until EOF and executed. If it is a ' - 'code\n' - 'object, it is simply executed. For the interpretation of a tuple, ' - 'see\n' - "below. In all cases, the code that's executed is expected to be " - 'valid\n' - 'as file input (see section File input). Be aware that the "return"\n' - 'and "yield" statements may not be used outside of function ' - 'definitions\n' - 'even within the context of code passed to the "exec" statement.\n' - '\n' - 'In all cases, if the optional parts are omitted, the code is ' - 'executed\n' - 'in the current scope. If only the first expression after "in" is\n' - 'specified, it should be a dictionary, which will be used for both ' - 'the\n' - 'global and the local variables. If two expressions are given, they\n' - 'are used for the global and local variables, respectively. If\n' - 'provided, *locals* can be any mapping object. Remember that at ' - 'module\n' - 'level, globals and locals are the same dictionary. If two separate\n' - 'objects are given as *globals* and *locals*, the code will be ' - 'executed\n' - 'as if it were embedded in a class definition.\n' - '\n' - 'The first expression may also be a tuple of length 2 or 3. In this\n' - 'case, the optional parts must be omitted. The form "exec(expr,\n' - 'globals)" is equivalent to "exec expr in globals", while the form\n' - '"exec(expr, globals, locals)" is equivalent to "exec expr in ' - 'globals,\n' - 'locals". The tuple form of "exec" provides compatibility with ' - 'Python\n' - '3, where "exec" is a function rather than a statement.\n' - '\n' - 'Changed in version 2.4: Formerly, *locals* was required to be a\n' - 'dictionary.\n' - '\n' - 'As a side effect, an implementation may insert additional keys into\n' - 'the dictionaries given besides those corresponding to variable ' - 'names\n' - 'set by the executed code. For example, the current implementation ' - 'may\n' - 'add a reference to the dictionary of the built-in module ' - '"__builtin__"\n' - 'under the key "__builtins__" (!).\n' - '\n' - "**Programmer's hints:** dynamic evaluation of expressions is " - 'supported\n' - 'by the built-in function "eval()". The built-in functions ' - '"globals()"\n' - 'and "locals()" return the current global and local dictionary,\n' - 'respectively, which may be useful to pass around for use by "exec".\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] Note that the parser only accepts the Unix-style end of line\n' - ' convention. If you are reading the code from a file, make sure ' - 'to\n' - ' use *universal newlines* mode to convert Windows or Mac-style\n' - ' newlines.\n', - 'execmodel': '\n' - 'Execution model\n' - '***************\n' - '\n' - '\n' - 'Naming and binding\n' - '==================\n' - '\n' - '*Names* refer to objects. Names are introduced by name ' - 'binding\n' - 'operations. Each occurrence of a name in the program text ' - 'refers to\n' - 'the *binding* of that name established in the innermost ' - 'function block\n' - 'containing the use.\n' - '\n' - 'A *block* is a piece of Python program text that is executed as ' - 'a\n' - 'unit. The following are blocks: a module, a function body, and ' - 'a class\n' - 'definition. Each command typed interactively is a block. A ' - 'script\n' - 'file (a file given as standard input to the interpreter or ' - 'specified\n' - 'on the interpreter command line the first argument) is a code ' - 'block.\n' - 'A script command (a command specified on the interpreter ' - 'command line\n' - "with the '**-c**' option) is a code block. The file read by " - 'the\n' - 'built-in function "execfile()" is a code block. The string ' - 'argument\n' - 'passed to the built-in function "eval()" and to the "exec" ' - 'statement\n' - 'is a code block. The expression read and evaluated by the ' - 'built-in\n' - 'function "input()" is a code block.\n' - '\n' - 'A code block is executed in an *execution frame*. A frame ' - 'contains\n' - 'some administrative information (used for debugging) and ' - 'determines\n' - "where and how execution continues after the code block's " - 'execution has\n' - 'completed.\n' - '\n' - 'A *scope* defines the visibility of a name within a block. If ' - 'a local\n' - 'variable is defined in a block, its scope includes that block. ' - 'If the\n' - 'definition occurs in a function block, the scope extends to any ' - 'blocks\n' - 'contained within the defining one, unless a contained block ' - 'introduces\n' - 'a different binding for the name. The scope of names defined ' - 'in a\n' - 'class block is limited to the class block; it does not extend ' - 'to the\n' - 'code blocks of methods -- this includes generator expressions ' - 'since\n' - 'they are implemented using a function scope. This means that ' - 'the\n' - 'following will fail:\n' - '\n' - ' class A:\n' - ' a = 42\n' - ' b = list(a + i for i in range(10))\n' - '\n' - 'When a name is used in a code block, it is resolved using the ' - 'nearest\n' - 'enclosing scope. The set of all such scopes visible to a code ' - 'block\n' - "is called the block's *environment*.\n" - '\n' - 'If a name is bound in a block, it is a local variable of that ' - 'block.\n' - 'If a name is bound at the module level, it is a global ' - 'variable. (The\n' - 'variables of the module code block are local and global.) If ' - 'a\n' - 'variable is used in a code block but not defined there, it is a ' - '*free\n' - 'variable*.\n' - '\n' - 'When a name is not found at all, a "NameError" exception is ' - 'raised.\n' - 'If the name refers to a local variable that has not been bound, ' - 'a\n' - '"UnboundLocalError" exception is raised. "UnboundLocalError" ' - 'is a\n' - 'subclass of "NameError".\n' - '\n' - 'The following constructs bind names: formal parameters to ' - 'functions,\n' - '"import" statements, class and function definitions (these bind ' - 'the\n' - 'class or function name in the defining block), and targets that ' - 'are\n' - 'identifiers if occurring in an assignment, "for" loop header, ' - 'in the\n' - 'second position of an "except" clause header or after "as" in a ' - '"with"\n' - 'statement. The "import" statement of the form "from ... import ' - '*"\n' - 'binds all names defined in the imported module, except those ' - 'beginning\n' - 'with an underscore. This form may only be used at the module ' - 'level.\n' - '\n' - 'A target occurring in a "del" statement is also considered ' - 'bound for\n' - 'this purpose (though the actual semantics are to unbind the ' - 'name). It\n' - 'is illegal to unbind a name that is referenced by an enclosing ' - 'scope;\n' - 'the compiler will report a "SyntaxError".\n' - '\n' - 'Each assignment or import statement occurs within a block ' - 'defined by a\n' - 'class or function definition or at the module level (the ' - 'top-level\n' - 'code block).\n' - '\n' - 'If a name binding operation occurs anywhere within a code ' - 'block, all\n' - 'uses of the name within the block are treated as references to ' - 'the\n' - 'current block. This can lead to errors when a name is used ' - 'within a\n' - 'block before it is bound. This rule is subtle. Python lacks\n' - 'declarations and allows name binding operations to occur ' - 'anywhere\n' - 'within a code block. The local variables of a code block can ' - 'be\n' - 'determined by scanning the entire text of the block for name ' - 'binding\n' - 'operations.\n' - '\n' - 'If the global statement occurs within a block, all uses of the ' - 'name\n' - 'specified in the statement refer to the binding of that name in ' - 'the\n' - 'top-level namespace. Names are resolved in the top-level ' - 'namespace by\n' - 'searching the global namespace, i.e. the namespace of the ' - 'module\n' - 'containing the code block, and the builtins namespace, the ' - 'namespace\n' - 'of the module "__builtin__". The global namespace is searched ' - 'first.\n' - 'If the name is not found there, the builtins namespace is ' - 'searched.\n' - 'The global statement must precede all uses of the name.\n' - '\n' - 'The builtins namespace associated with the execution of a code ' - 'block\n' - 'is actually found by looking up the name "__builtins__" in its ' - 'global\n' - 'namespace; this should be a dictionary or a module (in the ' - 'latter case\n' - "the module's dictionary is used). By default, when in the " - '"__main__"\n' - 'module, "__builtins__" is the built-in module "__builtin__" ' - '(note: no\n' - '\'s\'); when in any other module, "__builtins__" is an alias ' - 'for the\n' - 'dictionary of the "__builtin__" module itself. "__builtins__" ' - 'can be\n' - 'set to a user-created dictionary to create a weak form of ' - 'restricted\n' - 'execution.\n' - '\n' - '**CPython implementation detail:** Users should not touch\n' - '"__builtins__"; it is strictly an implementation detail. ' - 'Users\n' - 'wanting to override values in the builtins namespace should ' - '"import"\n' - 'the "__builtin__" (no \'s\') module and modify its attributes\n' - 'appropriately.\n' - '\n' - 'The namespace for a module is automatically created the first ' - 'time a\n' - 'module is imported. The main module for a script is always ' - 'called\n' - '"__main__".\n' - '\n' - 'The "global" statement has the same scope as a name binding ' - 'operation\n' - 'in the same block. If the nearest enclosing scope for a free ' - 'variable\n' - 'contains a global statement, the free variable is treated as a ' - 'global.\n' - '\n' - 'A class definition is an executable statement that may use and ' - 'define\n' - 'names. These references follow the normal rules for name ' - 'resolution.\n' - 'The namespace of the class definition becomes the attribute ' - 'dictionary\n' - 'of the class. Names defined at the class scope are not visible ' - 'in\n' - 'methods.\n' - '\n' - '\n' - 'Interaction with dynamic features\n' - '---------------------------------\n' - '\n' - 'There are several cases where Python statements are illegal ' - 'when used\n' - 'in conjunction with nested scopes that contain free variables.\n' - '\n' - 'If a variable is referenced in an enclosing scope, it is ' - 'illegal to\n' - 'delete the name. An error will be reported at compile time.\n' - '\n' - 'If the wild card form of import --- "import *" --- is used in ' - 'a\n' - 'function and the function contains or is a nested block with ' - 'free\n' - 'variables, the compiler will raise a "SyntaxError".\n' - '\n' - 'If "exec" is used in a function and the function contains or is ' - 'a\n' - 'nested block with free variables, the compiler will raise a\n' - '"SyntaxError" unless the exec explicitly specifies the local ' - 'namespace\n' - 'for the "exec". (In other words, "exec obj" would be illegal, ' - 'but\n' - '"exec obj in ns" would be legal.)\n' - '\n' - 'The "eval()", "execfile()", and "input()" functions and the ' - '"exec"\n' - 'statement do not have access to the full environment for ' - 'resolving\n' - 'names. Names may be resolved in the local and global ' - 'namespaces of\n' - 'the caller. Free variables are not resolved in the nearest ' - 'enclosing\n' - 'namespace, but in the global namespace. [1] The "exec" ' - 'statement and\n' - 'the "eval()" and "execfile()" functions have optional arguments ' - 'to\n' - 'override the global and local namespace. If only one namespace ' - 'is\n' - 'specified, it is used for both.\n' - '\n' - '\n' - 'Exceptions\n' - '==========\n' - '\n' - 'Exceptions are a means of breaking out of the normal flow of ' - 'control\n' - 'of a code block in order to handle errors or other exceptional\n' - 'conditions. An exception is *raised* at the point where the ' - 'error is\n' - 'detected; it may be *handled* by the surrounding code block or ' - 'by any\n' - 'code block that directly or indirectly invoked the code block ' - 'where\n' - 'the error occurred.\n' - '\n' - 'The Python interpreter raises an exception when it detects a ' - 'run-time\n' - 'error (such as division by zero). A Python program can also\n' - 'explicitly raise an exception with the "raise" statement. ' - 'Exception\n' - 'handlers are specified with the "try" ... "except" statement. ' - 'The\n' - '"finally" clause of such a statement can be used to specify ' - 'cleanup\n' - 'code which does not handle the exception, but is executed ' - 'whether an\n' - 'exception occurred or not in the preceding code.\n' - '\n' - 'Python uses the "termination" model of error handling: an ' - 'exception\n' - 'handler can find out what happened and continue execution at an ' - 'outer\n' - 'level, but it cannot repair the cause of the error and retry ' - 'the\n' - 'failing operation (except by re-entering the offending piece of ' - 'code\n' - 'from the top).\n' - '\n' - 'When an exception is not handled at all, the interpreter ' - 'terminates\n' - 'execution of the program, or returns to its interactive main ' - 'loop. In\n' - 'either case, it prints a stack backtrace, except when the ' - 'exception is\n' - '"SystemExit".\n' - '\n' - 'Exceptions are identified by class instances. The "except" ' - 'clause is\n' - 'selected depending on the class of the instance: it must ' - 'reference the\n' - 'class of the instance or a base class thereof. The instance ' - 'can be\n' - 'received by the handler and can carry additional information ' - 'about the\n' - 'exceptional condition.\n' - '\n' - 'Exceptions can also be identified by strings, in which case ' - 'the\n' - '"except" clause is selected by object identity. An arbitrary ' - 'value\n' - 'can be raised along with the identifying string which can be ' - 'passed to\n' - 'the handler.\n' - '\n' - 'Note: Messages to exceptions are not part of the Python API. ' - 'Their\n' - ' contents may change from one version of Python to the next ' - 'without\n' - ' warning and should not be relied on by code which will run ' - 'under\n' - ' multiple versions of the interpreter.\n' - '\n' - 'See also the description of the "try" statement in section The ' - 'try\n' - 'statement and "raise" statement in section The raise ' - 'statement.\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] This limitation occurs because the code that is executed ' - 'by\n' - ' these operations is not available at the time the module ' - 'is\n' - ' compiled.\n', - 'exprlists': '\n' - 'Expression lists\n' - '****************\n' - '\n' - ' expression_list ::= expression ( "," expression )* [","]\n' - '\n' - 'An expression list containing at least one comma yields a ' - 'tuple. The\n' - 'length of the tuple is the number of expressions in the list. ' - 'The\n' - 'expressions are evaluated from left to right.\n' - '\n' - 'The trailing comma is required only to create a single tuple ' - '(a.k.a. a\n' - '*singleton*); it is optional in all other cases. A single ' - 'expression\n' - "without a trailing comma doesn't create a tuple, but rather " - 'yields the\n' - 'value of that expression. (To create an empty tuple, use an ' - 'empty pair\n' - 'of parentheses: "()".)\n', - 'floating': '\n' - 'Floating point literals\n' - '***********************\n' - '\n' - 'Floating point literals are described by the following lexical\n' - 'definitions:\n' - '\n' - ' floatnumber ::= pointfloat | exponentfloat\n' - ' pointfloat ::= [intpart] fraction | intpart "."\n' - ' exponentfloat ::= (intpart | pointfloat) exponent\n' - ' intpart ::= digit+\n' - ' fraction ::= "." digit+\n' - ' exponent ::= ("e" | "E") ["+" | "-"] digit+\n' - '\n' - 'Note that the integer and exponent parts of floating point ' - 'numbers can\n' - 'look like octal integers, but are interpreted using radix 10. ' - 'For\n' - 'example, "077e010" is legal, and denotes the same number as ' - '"77e10".\n' - 'The allowed range of floating point literals is implementation-\n' - 'dependent. Some examples of floating point literals:\n' - '\n' - ' 3.14 10. .001 1e100 3.14e-10 0e0\n' - '\n' - 'Note that numeric literals do not include a sign; a phrase like ' - '"-1"\n' - 'is actually an expression composed of the unary operator "-" and ' - 'the\n' - 'literal "1".\n', - 'for': '\n' - 'The "for" statement\n' - '*******************\n' - '\n' - 'The "for" statement is used to iterate over the elements of a ' - 'sequence\n' - '(such as a string, tuple or list) or other iterable object:\n' - '\n' - ' for_stmt ::= "for" target_list "in" expression_list ":" suite\n' - ' ["else" ":" suite]\n' - '\n' - 'The expression list is evaluated once; it should yield an iterable\n' - 'object. An iterator is created for the result of the\n' - '"expression_list". The suite is then executed once for each item\n' - 'provided by the iterator, in the order of ascending indices. Each\n' - 'item in turn is assigned to the target list using the standard rules\n' - 'for assignments, and then the suite is executed. When the items are\n' - 'exhausted (which is immediately when the sequence is empty), the ' - 'suite\n' - 'in the "else" clause, if present, is executed, and the loop\n' - 'terminates.\n' - '\n' - 'A "break" statement executed in the first suite terminates the loop\n' - 'without executing the "else" clause\'s suite. A "continue" ' - 'statement\n' - 'executed in the first suite skips the rest of the suite and ' - 'continues\n' - 'with the next item, or with the "else" clause if there was no next\n' - 'item.\n' - '\n' - 'The suite may assign to the variable(s) in the target list; this ' - 'does\n' - 'not affect the next item assigned to it.\n' - '\n' - 'The target list is not deleted when the loop is finished, but if the\n' - 'sequence is empty, it will not have been assigned to at all by the\n' - 'loop. Hint: the built-in function "range()" returns a sequence of\n' - 'integers suitable to emulate the effect of Pascal\'s "for i := a to ' - 'b\n' - 'do"; e.g., "range(3)" returns the list "[0, 1, 2]".\n' - '\n' - 'Note: There is a subtlety when the sequence is being modified by the\n' - ' loop (this can only occur for mutable sequences, i.e. lists). An\n' - ' internal counter is used to keep track of which item is used next,\n' - ' and this is incremented on each iteration. When this counter has\n' - ' reached the length of the sequence the loop terminates. This ' - 'means\n' - ' that if the suite deletes the current (or a previous) item from ' - 'the\n' - ' sequence, the next item will be skipped (since it gets the index ' - 'of\n' - ' the current item which has already been treated). Likewise, if ' - 'the\n' - ' suite inserts an item in the sequence before the current item, the\n' - ' current item will be treated again the next time through the loop.\n' - ' This can lead to nasty bugs that can be avoided by making a\n' - ' temporary copy using a slice of the whole sequence, e.g.,\n' - '\n' - ' for x in a[:]:\n' - ' if x < 0: a.remove(x)\n', - 'formatstrings': '\n' - 'Format String Syntax\n' - '********************\n' - '\n' - 'The "str.format()" method and the "Formatter" class share ' - 'the same\n' - 'syntax for format strings (although in the case of ' - '"Formatter",\n' - 'subclasses can define their own format string syntax).\n' - '\n' - 'Format strings contain "replacement fields" surrounded by ' - 'curly braces\n' - '"{}". Anything that is not contained in braces is ' - 'considered literal\n' - 'text, which is copied unchanged to the output. If you need ' - 'to include\n' - 'a brace character in the literal text, it can be escaped by ' - 'doubling:\n' - '"{{" and "}}".\n' - '\n' - 'The grammar for a replacement field is as follows:\n' - '\n' - ' replacement_field ::= "{" [field_name] ["!" ' - 'conversion] [":" format_spec] "}"\n' - ' field_name ::= arg_name ("." attribute_name | ' - '"[" element_index "]")*\n' - ' arg_name ::= [identifier | integer]\n' - ' attribute_name ::= identifier\n' - ' element_index ::= integer | index_string\n' - ' index_string ::= <any source character except ' - '"]"> +\n' - ' conversion ::= "r" | "s"\n' - ' format_spec ::= <described in the next ' - 'section>\n' - '\n' - 'In less formal terms, the replacement field can start with ' - 'a\n' - '*field_name* that specifies the object whose value is to be ' - 'formatted\n' - 'and inserted into the output instead of the replacement ' - 'field. The\n' - '*field_name* is optionally followed by a *conversion* ' - 'field, which is\n' - 'preceded by an exclamation point "\'!\'", and a ' - '*format_spec*, which is\n' - 'preceded by a colon "\':\'". These specify a non-default ' - 'format for the\n' - 'replacement value.\n' - '\n' - 'See also the Format Specification Mini-Language section.\n' - '\n' - 'The *field_name* itself begins with an *arg_name* that is ' - 'either a\n' - "number or a keyword. If it's a number, it refers to a " - 'positional\n' - "argument, and if it's a keyword, it refers to a named " - 'keyword\n' - 'argument. If the numerical arg_names in a format string ' - 'are 0, 1, 2,\n' - '... in sequence, they can all be omitted (not just some) ' - 'and the\n' - 'numbers 0, 1, 2, ... will be automatically inserted in that ' - 'order.\n' - 'Because *arg_name* is not quote-delimited, it is not ' - 'possible to\n' - 'specify arbitrary dictionary keys (e.g., the strings ' - '"\'10\'" or\n' - '"\':-]\'") within a format string. The *arg_name* can be ' - 'followed by any\n' - 'number of index or attribute expressions. An expression of ' - 'the form\n' - '"\'.name\'" selects the named attribute using "getattr()", ' - 'while an\n' - 'expression of the form "\'[index]\'" does an index lookup ' - 'using\n' - '"__getitem__()".\n' - '\n' - 'Changed in version 2.7: The positional argument specifiers ' - 'can be\n' - 'omitted, so "\'{} {}\'" is equivalent to "\'{0} {1}\'".\n' - '\n' - 'Some simple format string examples:\n' - '\n' - ' "First, thou shalt count to {0}" # References first ' - 'positional argument\n' - ' "Bring me a {}" # Implicitly ' - 'references the first positional argument\n' - ' "From {} to {}" # Same as "From {0} to ' - '{1}"\n' - ' "My quest is {name}" # References keyword ' - "argument 'name'\n" - ' "Weight in tons {0.weight}" # \'weight\' attribute ' - 'of first positional arg\n' - ' "Units destroyed: {players[0]}" # First element of ' - "keyword argument 'players'.\n" - '\n' - 'The *conversion* field causes a type coercion before ' - 'formatting.\n' - 'Normally, the job of formatting a value is done by the ' - '"__format__()"\n' - 'method of the value itself. However, in some cases it is ' - 'desirable to\n' - 'force a type to be formatted as a string, overriding its ' - 'own\n' - 'definition of formatting. By converting the value to a ' - 'string before\n' - 'calling "__format__()", the normal formatting logic is ' - 'bypassed.\n' - '\n' - 'Two conversion flags are currently supported: "\'!s\'" ' - 'which calls\n' - '"str()" on the value, and "\'!r\'" which calls "repr()".\n' - '\n' - 'Some examples:\n' - '\n' - ' "Harold\'s a clever {0!s}" # Calls str() on the ' - 'argument first\n' - ' "Bring out the holy {name!r}" # Calls repr() on the ' - 'argument first\n' - '\n' - 'The *format_spec* field contains a specification of how the ' - 'value\n' - 'should be presented, including such details as field width, ' - 'alignment,\n' - 'padding, decimal precision and so on. Each value type can ' - 'define its\n' - 'own "formatting mini-language" or interpretation of the ' - '*format_spec*.\n' - '\n' - 'Most built-in types support a common formatting ' - 'mini-language, which\n' - 'is described in the next section.\n' - '\n' - 'A *format_spec* field can also include nested replacement ' - 'fields\n' - 'within it. These nested replacement fields may contain a ' - 'field name,\n' - 'conversion flag and format specification, but deeper ' - 'nesting is not\n' - 'allowed. The replacement fields within the format_spec ' - 'are\n' - 'substituted before the *format_spec* string is interpreted. ' - 'This\n' - 'allows the formatting of a value to be dynamically ' - 'specified.\n' - '\n' - 'See the Format examples section for some examples.\n' - '\n' - '\n' - 'Format Specification Mini-Language\n' - '==================================\n' - '\n' - '"Format specifications" are used within replacement fields ' - 'contained\n' - 'within a format string to define how individual values are ' - 'presented\n' - '(see Format String Syntax). They can also be passed ' - 'directly to the\n' - 'built-in "format()" function. Each formattable type may ' - 'define how\n' - 'the format specification is to be interpreted.\n' - '\n' - 'Most built-in types implement the following options for ' - 'format\n' - 'specifications, although some of the formatting options are ' - 'only\n' - 'supported by the numeric types.\n' - '\n' - 'A general convention is that an empty format string ("""") ' - 'produces\n' - 'the same result as if you had called "str()" on the value. ' - 'A non-empty\n' - 'format string typically modifies the result.\n' - '\n' - 'The general form of a *standard format specifier* is:\n' - '\n' - ' format_spec ::= ' - '[[fill]align][sign][#][0][width][,][.precision][type]\n' - ' fill ::= <any character>\n' - ' align ::= "<" | ">" | "=" | "^"\n' - ' sign ::= "+" | "-" | " "\n' - ' width ::= integer\n' - ' precision ::= integer\n' - ' type ::= "b" | "c" | "d" | "e" | "E" | "f" | "F" ' - '| "g" | "G" | "n" | "o" | "s" | "x" | "X" | "%"\n' - '\n' - 'If a valid *align* value is specified, it can be preceded ' - 'by a *fill*\n' - 'character that can be any character and defaults to a space ' - 'if\n' - 'omitted. It is not possible to use a literal curly brace ' - '(""{"" or\n' - '""}"") as the *fill* character when using the ' - '"str.format()" method.\n' - 'However, it is possible to insert a curly brace with a ' - 'nested\n' - "replacement field. This limitation doesn't affect the " - '"format()"\n' - 'function.\n' - '\n' - 'The meaning of the various alignment options is as ' - 'follows:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Option | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'<\'" | Forces the field to be left-aligned ' - 'within the available |\n' - ' | | space (this is the default for most ' - 'objects). |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'>\'" | Forces the field to be right-aligned ' - 'within the available |\n' - ' | | space (this is the default for ' - 'numbers). |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'=\'" | Forces the padding to be placed after ' - 'the sign (if any) |\n' - ' | | but before the digits. This is used for ' - 'printing fields |\n' - " | | in the form '+000000120'. This alignment " - 'option is only |\n' - ' | | valid for numeric types. It becomes the ' - "default when '0' |\n" - ' | | immediately precedes the field ' - 'width. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'^\'" | Forces the field to be centered within ' - 'the available |\n' - ' | | ' - 'space. ' - '|\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - 'Note that unless a minimum field width is defined, the ' - 'field width\n' - 'will always be the same size as the data to fill it, so ' - 'that the\n' - 'alignment option has no meaning in this case.\n' - '\n' - 'The *sign* option is only valid for number types, and can ' - 'be one of\n' - 'the following:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Option | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'+\'" | indicates that a sign should be used for ' - 'both positive as |\n' - ' | | well as negative ' - 'numbers. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'-\'" | indicates that a sign should be used ' - 'only for negative |\n' - ' | | numbers (this is the default ' - 'behavior). |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | space | indicates that a leading space should be ' - 'used on positive |\n' - ' | | numbers, and a minus sign on negative ' - 'numbers. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - 'The "\'#\'" option is only valid for integers, and only for ' - 'binary,\n' - 'octal, or hexadecimal output. If present, it specifies ' - 'that the\n' - 'output will be prefixed by "\'0b\'", "\'0o\'", or "\'0x\'", ' - 'respectively.\n' - '\n' - 'The "\',\'" option signals the use of a comma for a ' - 'thousands separator.\n' - 'For a locale aware separator, use the "\'n\'" integer ' - 'presentation type\n' - 'instead.\n' - '\n' - 'Changed in version 2.7: Added the "\',\'" option (see also ' - '**PEP 378**).\n' - '\n' - '*width* is a decimal integer defining the minimum field ' - 'width. If not\n' - 'specified, then the field width will be determined by the ' - 'content.\n' - '\n' - 'When no explicit alignment is given, preceding the *width* ' - 'field by a\n' - 'zero ("\'0\'") character enables sign-aware zero-padding ' - 'for numeric\n' - 'types. This is equivalent to a *fill* character of "\'0\'" ' - 'with an\n' - '*alignment* type of "\'=\'".\n' - '\n' - 'The *precision* is a decimal number indicating how many ' - 'digits should\n' - 'be displayed after the decimal point for a floating point ' - 'value\n' - 'formatted with "\'f\'" and "\'F\'", or before and after the ' - 'decimal point\n' - 'for a floating point value formatted with "\'g\'" or ' - '"\'G\'". For non-\n' - 'number types the field indicates the maximum field size - ' - 'in other\n' - 'words, how many characters will be used from the field ' - 'content. The\n' - '*precision* is not allowed for integer values.\n' - '\n' - 'Finally, the *type* determines how the data should be ' - 'presented.\n' - '\n' - 'The available string presentation types are:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Type | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'s\'" | String format. This is the default type ' - 'for strings and |\n' - ' | | may be ' - 'omitted. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | None | The same as ' - '"\'s\'". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - 'The available integer presentation types are:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Type | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'b\'" | Binary format. Outputs the number in ' - 'base 2. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'c\'" | Character. Converts the integer to the ' - 'corresponding |\n' - ' | | unicode character before ' - 'printing. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'d\'" | Decimal Integer. Outputs the number in ' - 'base 10. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'o\'" | Octal format. Outputs the number in base ' - '8. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'x\'" | Hex format. Outputs the number in base ' - '16, using lower- |\n' - ' | | case letters for the digits above ' - '9. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'X\'" | Hex format. Outputs the number in base ' - '16, using upper- |\n' - ' | | case letters for the digits above ' - '9. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'n\'" | Number. This is the same as "\'d\'", ' - 'except that it uses the |\n' - ' | | current locale setting to insert the ' - 'appropriate number |\n' - ' | | separator ' - 'characters. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | None | The same as ' - '"\'d\'". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - 'In addition to the above presentation types, integers can ' - 'be formatted\n' - 'with the floating point presentation types listed below ' - '(except "\'n\'"\n' - 'and "None"). When doing so, "float()" is used to convert ' - 'the integer\n' - 'to a floating point number before formatting.\n' - '\n' - 'The available presentation types for floating point and ' - 'decimal values\n' - 'are:\n' - '\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | Type | ' - 'Meaning ' - '|\n' - ' ' - '+===========+============================================================+\n' - ' | "\'e\'" | Exponent notation. Prints the number in ' - 'scientific |\n' - " | | notation using the letter 'e' to indicate " - 'the exponent. |\n' - ' | | The default precision is ' - '"6". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'E\'" | Exponent notation. Same as "\'e\'" ' - 'except it uses an upper |\n' - " | | case 'E' as the separator " - 'character. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'f\'" | Fixed point. Displays the number as a ' - 'fixed-point number. |\n' - ' | | The default precision is ' - '"6". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'F\'" | Fixed point. Same as ' - '"\'f\'". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'g\'" | General format. For a given precision ' - '"p >= 1", this |\n' - ' | | rounds the number to "p" significant ' - 'digits and then |\n' - ' | | formats the result in either fixed-point ' - 'format or in |\n' - ' | | scientific notation, depending on its ' - 'magnitude. The |\n' - ' | | precise rules are as follows: suppose that ' - 'the result |\n' - ' | | formatted with presentation type "\'e\'" ' - 'and precision "p-1" |\n' - ' | | would have exponent "exp". Then if "-4 <= ' - 'exp < p", the |\n' - ' | | number is formatted with presentation type ' - '"\'f\'" and |\n' - ' | | precision "p-1-exp". Otherwise, the ' - 'number is formatted |\n' - ' | | with presentation type "\'e\'" and ' - 'precision "p-1". In both |\n' - ' | | cases insignificant trailing zeros are ' - 'removed from the |\n' - ' | | significand, and the decimal point is also ' - 'removed if |\n' - ' | | there are no remaining digits following ' - 'it. Positive and |\n' - ' | | negative infinity, positive and negative ' - 'zero, and nans, |\n' - ' | | are formatted as "inf", "-inf", "0", "-0" ' - 'and "nan" |\n' - ' | | respectively, regardless of the ' - 'precision. A precision of |\n' - ' | | "0" is treated as equivalent to a ' - 'precision of "1". The |\n' - ' | | default precision is ' - '"6". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'G\'" | General format. Same as "\'g\'" except ' - 'switches to "\'E\'" if |\n' - ' | | the number gets too large. The ' - 'representations of infinity |\n' - ' | | and NaN are uppercased, ' - 'too. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'n\'" | Number. This is the same as "\'g\'", ' - 'except that it uses the |\n' - ' | | current locale setting to insert the ' - 'appropriate number |\n' - ' | | separator ' - 'characters. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | "\'%\'" | Percentage. Multiplies the number by 100 ' - 'and displays in |\n' - ' | | fixed ("\'f\'") format, followed by a ' - 'percent sign. |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - ' | None | The same as ' - '"\'g\'". |\n' - ' ' - '+-----------+------------------------------------------------------------+\n' - '\n' - '\n' - 'Format examples\n' - '===============\n' - '\n' - 'This section contains examples of the "str.format()" syntax ' - 'and\n' - 'comparison with the old "%"-formatting.\n' - '\n' - 'In most of the cases the syntax is similar to the old ' - '"%"-formatting,\n' - 'with the addition of the "{}" and with ":" used instead of ' - '"%". For\n' - 'example, "\'%03.2f\'" can be translated to "\'{:03.2f}\'".\n' - '\n' - 'The new format syntax also supports new and different ' - 'options, shown\n' - 'in the follow examples.\n' - '\n' - 'Accessing arguments by position:\n' - '\n' - " >>> '{0}, {1}, {2}'.format('a', 'b', 'c')\n" - " 'a, b, c'\n" - " >>> '{}, {}, {}'.format('a', 'b', 'c') # 2.7+ only\n" - " 'a, b, c'\n" - " >>> '{2}, {1}, {0}'.format('a', 'b', 'c')\n" - " 'c, b, a'\n" - " >>> '{2}, {1}, {0}'.format(*'abc') # unpacking " - 'argument sequence\n' - " 'c, b, a'\n" - " >>> '{0}{1}{0}'.format('abra', 'cad') # arguments' " - 'indices can be repeated\n' - " 'abracadabra'\n" - '\n' - 'Accessing arguments by name:\n' - '\n' - " >>> 'Coordinates: {latitude}, " - "{longitude}'.format(latitude='37.24N', " - "longitude='-115.81W')\n" - " 'Coordinates: 37.24N, -115.81W'\n" - " >>> coord = {'latitude': '37.24N', 'longitude': " - "'-115.81W'}\n" - " >>> 'Coordinates: {latitude}, " - "{longitude}'.format(**coord)\n" - " 'Coordinates: 37.24N, -115.81W'\n" - '\n' - "Accessing arguments' attributes:\n" - '\n' - ' >>> c = 3-5j\n' - " >>> ('The complex number {0} is formed from the real " - "part {0.real} '\n" - " ... 'and the imaginary part {0.imag}.').format(c)\n" - " 'The complex number (3-5j) is formed from the real part " - "3.0 and the imaginary part -5.0.'\n" - ' >>> class Point(object):\n' - ' ... def __init__(self, x, y):\n' - ' ... self.x, self.y = x, y\n' - ' ... def __str__(self):\n' - " ... return 'Point({self.x}, " - "{self.y})'.format(self=self)\n" - ' ...\n' - ' >>> str(Point(4, 2))\n' - " 'Point(4, 2)'\n" - '\n' - "Accessing arguments' items:\n" - '\n' - ' >>> coord = (3, 5)\n' - " >>> 'X: {0[0]}; Y: {0[1]}'.format(coord)\n" - " 'X: 3; Y: 5'\n" - '\n' - 'Replacing "%s" and "%r":\n' - '\n' - ' >>> "repr() shows quotes: {!r}; str() doesn\'t: ' - '{!s}".format(\'test1\', \'test2\')\n' - ' "repr() shows quotes: \'test1\'; str() doesn\'t: test2"\n' - '\n' - 'Aligning the text and specifying a width:\n' - '\n' - " >>> '{:<30}'.format('left aligned')\n" - " 'left aligned '\n" - " >>> '{:>30}'.format('right aligned')\n" - " ' right aligned'\n" - " >>> '{:^30}'.format('centered')\n" - " ' centered '\n" - " >>> '{:*^30}'.format('centered') # use '*' as a fill " - 'char\n' - " '***********centered***********'\n" - '\n' - 'Replacing "%+f", "%-f", and "% f" and specifying a sign:\n' - '\n' - " >>> '{:+f}; {:+f}'.format(3.14, -3.14) # show it " - 'always\n' - " '+3.140000; -3.140000'\n" - " >>> '{: f}; {: f}'.format(3.14, -3.14) # show a space " - 'for positive numbers\n' - " ' 3.140000; -3.140000'\n" - " >>> '{:-f}; {:-f}'.format(3.14, -3.14) # show only the " - "minus -- same as '{:f}; {:f}'\n" - " '3.140000; -3.140000'\n" - '\n' - 'Replacing "%x" and "%o" and converting the value to ' - 'different bases:\n' - '\n' - ' >>> # format also supports binary numbers\n' - ' >>> "int: {0:d}; hex: {0:x}; oct: {0:o}; bin: ' - '{0:b}".format(42)\n' - " 'int: 42; hex: 2a; oct: 52; bin: 101010'\n" - ' >>> # with 0x, 0o, or 0b as prefix:\n' - ' >>> "int: {0:d}; hex: {0:#x}; oct: {0:#o}; bin: ' - '{0:#b}".format(42)\n' - " 'int: 42; hex: 0x2a; oct: 0o52; bin: 0b101010'\n" - '\n' - 'Using the comma as a thousands separator:\n' - '\n' - " >>> '{:,}'.format(1234567890)\n" - " '1,234,567,890'\n" - '\n' - 'Expressing a percentage:\n' - '\n' - ' >>> points = 19.5\n' - ' >>> total = 22\n' - " >>> 'Correct answers: {:.2%}'.format(points/total)\n" - " 'Correct answers: 88.64%'\n" - '\n' - 'Using type-specific formatting:\n' - '\n' - ' >>> import datetime\n' - ' >>> d = datetime.datetime(2010, 7, 4, 12, 15, 58)\n' - " >>> '{:%Y-%m-%d %H:%M:%S}'.format(d)\n" - " '2010-07-04 12:15:58'\n" - '\n' - 'Nesting arguments and more complex examples:\n' - '\n' - " >>> for align, text in zip('<^>', ['left', 'center', " - "'right']):\n" - " ... '{0:{fill}{align}16}'.format(text, fill=align, " - 'align=align)\n' - ' ...\n' - " 'left<<<<<<<<<<<<'\n" - " '^^^^^center^^^^^'\n" - " '>>>>>>>>>>>right'\n" - ' >>>\n' - ' >>> octets = [192, 168, 0, 1]\n' - " >>> '{:02X}{:02X}{:02X}{:02X}'.format(*octets)\n" - " 'C0A80001'\n" - ' >>> int(_, 16)\n' - ' 3232235521\n' - ' >>>\n' - ' >>> width = 5\n' - ' >>> for num in range(5,12):\n' - " ... for base in 'dXob':\n" - " ... print '{0:{width}{base}}'.format(num, " - 'base=base, width=width),\n' - ' ... print\n' - ' ...\n' - ' 5 5 5 101\n' - ' 6 6 6 110\n' - ' 7 7 7 111\n' - ' 8 8 10 1000\n' - ' 9 9 11 1001\n' - ' 10 A 12 1010\n' - ' 11 B 13 1011\n', - 'function': '\n' - 'Function definitions\n' - '********************\n' - '\n' - 'A function definition defines a user-defined function object ' - '(see\n' - 'section The standard type hierarchy):\n' - '\n' - ' decorated ::= decorators (classdef | funcdef)\n' - ' decorators ::= decorator+\n' - ' decorator ::= "@" dotted_name ["(" [argument_list [","]] ' - '")"] NEWLINE\n' - ' funcdef ::= "def" funcname "(" [parameter_list] ")" ' - '":" suite\n' - ' dotted_name ::= identifier ("." identifier)*\n' - ' parameter_list ::= (defparameter ",")*\n' - ' ( "*" identifier ["," "**" identifier]\n' - ' | "**" identifier\n' - ' | defparameter [","] )\n' - ' defparameter ::= parameter ["=" expression]\n' - ' sublist ::= parameter ("," parameter)* [","]\n' - ' parameter ::= identifier | "(" sublist ")"\n' - ' funcname ::= identifier\n' - '\n' - 'A function definition is an executable statement. Its execution ' - 'binds\n' - 'the function name in the current local namespace to a function ' - 'object\n' - '(a wrapper around the executable code for the function). This\n' - 'function object contains a reference to the current global ' - 'namespace\n' - 'as the global namespace to be used when the function is called.\n' - '\n' - 'The function definition does not execute the function body; this ' - 'gets\n' - 'executed only when the function is called. [3]\n' - '\n' - 'A function definition may be wrapped by one or more *decorator*\n' - 'expressions. Decorator expressions are evaluated when the ' - 'function is\n' - 'defined, in the scope that contains the function definition. ' - 'The\n' - 'result must be a callable, which is invoked with the function ' - 'object\n' - 'as the only argument. The returned value is bound to the ' - 'function name\n' - 'instead of the function object. Multiple decorators are applied ' - 'in\n' - 'nested fashion. For example, the following code:\n' - '\n' - ' @f1(arg)\n' - ' @f2\n' - ' def func(): pass\n' - '\n' - 'is equivalent to:\n' - '\n' - ' def func(): pass\n' - ' func = f1(arg)(f2(func))\n' - '\n' - 'When one or more top-level *parameters* have the form ' - '*parameter* "="\n' - '*expression*, the function is said to have "default parameter ' - 'values."\n' - 'For a parameter with a default value, the corresponding ' - '*argument* may\n' - "be omitted from a call, in which case the parameter's default " - 'value is\n' - 'substituted. If a parameter has a default value, all following\n' - 'parameters must also have a default value --- this is a ' - 'syntactic\n' - 'restriction that is not expressed by the grammar.\n' - '\n' - '**Default parameter values are evaluated when the function ' - 'definition\n' - 'is executed.** This means that the expression is evaluated ' - 'once, when\n' - 'the function is defined, and that the same "pre-computed" value ' - 'is\n' - 'used for each call. This is especially important to understand ' - 'when a\n' - 'default parameter is a mutable object, such as a list or a ' - 'dictionary:\n' - 'if the function modifies the object (e.g. by appending an item ' - 'to a\n' - 'list), the default value is in effect modified. This is ' - 'generally not\n' - 'what was intended. A way around this is to use "None" as the\n' - 'default, and explicitly test for it in the body of the function, ' - 'e.g.:\n' - '\n' - ' def whats_on_the_telly(penguin=None):\n' - ' if penguin is None:\n' - ' penguin = []\n' - ' penguin.append("property of the zoo")\n' - ' return penguin\n' - '\n' - 'Function call semantics are described in more detail in section ' - 'Calls.\n' - 'A function call always assigns values to all parameters ' - 'mentioned in\n' - 'the parameter list, either from position arguments, from ' - 'keyword\n' - 'arguments, or from default values. If the form ""*identifier"" ' - 'is\n' - 'present, it is initialized to a tuple receiving any excess ' - 'positional\n' - 'parameters, defaulting to the empty tuple. If the form\n' - '""**identifier"" is present, it is initialized to a new ' - 'dictionary\n' - 'receiving any excess keyword arguments, defaulting to a new ' - 'empty\n' - 'dictionary.\n' - '\n' - 'It is also possible to create anonymous functions (functions not ' - 'bound\n' - 'to a name), for immediate use in expressions. This uses lambda\n' - 'expressions, described in section Lambdas. Note that the ' - 'lambda\n' - 'expression is merely a shorthand for a simplified function ' - 'definition;\n' - 'a function defined in a ""def"" statement can be passed around ' - 'or\n' - 'assigned to another name just like a function defined by a ' - 'lambda\n' - 'expression. The ""def"" form is actually more powerful since ' - 'it\n' - 'allows the execution of multiple statements.\n' - '\n' - "**Programmer's note:** Functions are first-class objects. A " - '""def""\n' - 'form executed inside a function definition defines a local ' - 'function\n' - 'that can be returned or passed around. Free variables used in ' - 'the\n' - 'nested function can access the local variables of the function\n' - 'containing the def. See section Naming and binding for ' - 'details.\n', - 'global': '\n' - 'The "global" statement\n' - '**********************\n' - '\n' - ' global_stmt ::= "global" identifier ("," identifier)*\n' - '\n' - 'The "global" statement is a declaration which holds for the ' - 'entire\n' - 'current code block. It means that the listed identifiers are to ' - 'be\n' - 'interpreted as globals. It would be impossible to assign to a ' - 'global\n' - 'variable without "global", although free variables may refer to\n' - 'globals without being declared global.\n' - '\n' - 'Names listed in a "global" statement must not be used in the same ' - 'code\n' - 'block textually preceding that "global" statement.\n' - '\n' - 'Names listed in a "global" statement must not be defined as ' - 'formal\n' - 'parameters or in a "for" loop control target, "class" definition,\n' - 'function definition, or "import" statement.\n' - '\n' - '**CPython implementation detail:** The current implementation does ' - 'not\n' - 'enforce the latter two restrictions, but programs should not ' - 'abuse\n' - 'this freedom, as future implementations may enforce them or ' - 'silently\n' - 'change the meaning of the program.\n' - '\n' - '**Programmer\'s note:** "global" is a directive to the parser. ' - 'It\n' - 'applies only to code parsed at the same time as the "global"\n' - 'statement. In particular, a "global" statement contained in an ' - '"exec"\n' - 'statement does not affect the code block *containing* the "exec"\n' - 'statement, and code contained in an "exec" statement is unaffected ' - 'by\n' - '"global" statements in the code containing the "exec" statement. ' - 'The\n' - 'same applies to the "eval()", "execfile()" and "compile()" ' - 'functions.\n', - 'id-classes': '\n' - 'Reserved classes of identifiers\n' - '*******************************\n' - '\n' - 'Certain classes of identifiers (besides keywords) have ' - 'special\n' - 'meanings. These classes are identified by the patterns of ' - 'leading and\n' - 'trailing underscore characters:\n' - '\n' - '"_*"\n' - ' Not imported by "from module import *". The special ' - 'identifier "_"\n' - ' is used in the interactive interpreter to store the result ' - 'of the\n' - ' last evaluation; it is stored in the "__builtin__" module. ' - 'When\n' - ' not in interactive mode, "_" has no special meaning and is ' - 'not\n' - ' defined. See section The import statement.\n' - '\n' - ' Note: The name "_" is often used in conjunction with\n' - ' internationalization; refer to the documentation for the\n' - ' "gettext" module for more information on this ' - 'convention.\n' - '\n' - '"__*__"\n' - ' System-defined names. These names are defined by the ' - 'interpreter\n' - ' and its implementation (including the standard library). ' - 'Current\n' - ' system names are discussed in the Special method names ' - 'section and\n' - ' elsewhere. More will likely be defined in future versions ' - 'of\n' - ' Python. *Any* use of "__*__" names, in any context, that ' - 'does not\n' - ' follow explicitly documented use, is subject to breakage ' - 'without\n' - ' warning.\n' - '\n' - '"__*"\n' - ' Class-private names. Names in this category, when used ' - 'within the\n' - ' context of a class definition, are re-written to use a ' - 'mangled form\n' - ' to help avoid name clashes between "private" attributes of ' - 'base and\n' - ' derived classes. See section Identifiers (Names).\n', - 'identifiers': '\n' - 'Identifiers and keywords\n' - '************************\n' - '\n' - 'Identifiers (also referred to as *names*) are described by ' - 'the\n' - 'following lexical definitions:\n' - '\n' - ' identifier ::= (letter|"_") (letter | digit | "_")*\n' - ' letter ::= lowercase | uppercase\n' - ' lowercase ::= "a"..."z"\n' - ' uppercase ::= "A"..."Z"\n' - ' digit ::= "0"..."9"\n' - '\n' - 'Identifiers are unlimited in length. Case is significant.\n' - '\n' - '\n' - 'Keywords\n' - '========\n' - '\n' - 'The following identifiers are used as reserved words, or ' - '*keywords* of\n' - 'the language, and cannot be used as ordinary identifiers. ' - 'They must\n' - 'be spelled exactly as written here:\n' - '\n' - ' and del from not while\n' - ' as elif global or with\n' - ' assert else if pass yield\n' - ' break except import print\n' - ' class exec in raise\n' - ' continue finally is return\n' - ' def for lambda try\n' - '\n' - 'Changed in version 2.4: "None" became a constant and is now ' - 'recognized\n' - 'by the compiler as a name for the built-in object "None". ' - 'Although it\n' - 'is not a keyword, you cannot assign a different object to ' - 'it.\n' - '\n' - 'Changed in version 2.5: Using "as" and "with" as identifiers ' - 'triggers\n' - 'a warning. To use them as keywords, enable the ' - '"with_statement"\n' - 'future feature .\n' - '\n' - 'Changed in version 2.6: "as" and "with" are full keywords.\n' - '\n' - '\n' - 'Reserved classes of identifiers\n' - '===============================\n' - '\n' - 'Certain classes of identifiers (besides keywords) have ' - 'special\n' - 'meanings. These classes are identified by the patterns of ' - 'leading and\n' - 'trailing underscore characters:\n' - '\n' - '"_*"\n' - ' Not imported by "from module import *". The special ' - 'identifier "_"\n' - ' is used in the interactive interpreter to store the result ' - 'of the\n' - ' last evaluation; it is stored in the "__builtin__" ' - 'module. When\n' - ' not in interactive mode, "_" has no special meaning and is ' - 'not\n' - ' defined. See section The import statement.\n' - '\n' - ' Note: The name "_" is often used in conjunction with\n' - ' internationalization; refer to the documentation for ' - 'the\n' - ' "gettext" module for more information on this ' - 'convention.\n' - '\n' - '"__*__"\n' - ' System-defined names. These names are defined by the ' - 'interpreter\n' - ' and its implementation (including the standard library). ' - 'Current\n' - ' system names are discussed in the Special method names ' - 'section and\n' - ' elsewhere. More will likely be defined in future versions ' - 'of\n' - ' Python. *Any* use of "__*__" names, in any context, that ' - 'does not\n' - ' follow explicitly documented use, is subject to breakage ' - 'without\n' - ' warning.\n' - '\n' - '"__*"\n' - ' Class-private names. Names in this category, when used ' - 'within the\n' - ' context of a class definition, are re-written to use a ' - 'mangled form\n' - ' to help avoid name clashes between "private" attributes of ' - 'base and\n' - ' derived classes. See section Identifiers (Names).\n', - 'if': '\n' - 'The "if" statement\n' - '******************\n' - '\n' - 'The "if" statement is used for conditional execution:\n' - '\n' - ' if_stmt ::= "if" expression ":" suite\n' - ' ( "elif" expression ":" suite )*\n' - ' ["else" ":" suite]\n' - '\n' - 'It selects exactly one of the suites by evaluating the expressions ' - 'one\n' - 'by one until one is found to be true (see section Boolean operations\n' - 'for the definition of true and false); then that suite is executed\n' - '(and no other part of the "if" statement is executed or evaluated).\n' - 'If all expressions are false, the suite of the "else" clause, if\n' - 'present, is executed.\n', - 'imaginary': '\n' - 'Imaginary literals\n' - '******************\n' - '\n' - 'Imaginary literals are described by the following lexical ' - 'definitions:\n' - '\n' - ' imagnumber ::= (floatnumber | intpart) ("j" | "J")\n' - '\n' - 'An imaginary literal yields a complex number with a real part ' - 'of 0.0.\n' - 'Complex numbers are represented as a pair of floating point ' - 'numbers\n' - 'and have the same restrictions on their range. To create a ' - 'complex\n' - 'number with a nonzero real part, add a floating point number to ' - 'it,\n' - 'e.g., "(3+4j)". Some examples of imaginary literals:\n' - '\n' - ' 3.14j 10.j 10j .001j 1e100j 3.14e-10j\n', - 'import': '\n' - 'The "import" statement\n' - '**********************\n' - '\n' - ' import_stmt ::= "import" module ["as" name] ( "," module ' - '["as" name] )*\n' - ' | "from" relative_module "import" identifier ' - '["as" name]\n' - ' ( "," identifier ["as" name] )*\n' - ' | "from" relative_module "import" "(" ' - 'identifier ["as" name]\n' - ' ( "," identifier ["as" name] )* [","] ")"\n' - ' | "from" module "import" "*"\n' - ' module ::= (identifier ".")* identifier\n' - ' relative_module ::= "."* module | "."+\n' - ' name ::= identifier\n' - '\n' - 'Import statements are executed in two steps: (1) find a module, ' - 'and\n' - 'initialize it if necessary; (2) define a name or names in the ' - 'local\n' - 'namespace (of the scope where the "import" statement occurs). The\n' - 'statement comes in two forms differing on whether it uses the ' - '"from"\n' - 'keyword. The first form (without "from") repeats these steps for ' - 'each\n' - 'identifier in the list. The form with "from" performs step (1) ' - 'once,\n' - 'and then performs step (2) repeatedly.\n' - '\n' - 'To understand how step (1) occurs, one must first understand how\n' - 'Python handles hierarchical naming of modules. To help organize\n' - 'modules and provide a hierarchy in naming, Python has a concept ' - 'of\n' - 'packages. A package can contain other packages and modules while\n' - 'modules cannot contain other modules or packages. From a file ' - 'system\n' - 'perspective, packages are directories and modules are files.\n' - '\n' - 'Once the name of the module is known (unless otherwise specified, ' - 'the\n' - 'term "module" will refer to both packages and modules), searching ' - 'for\n' - 'the module or package can begin. The first place checked is\n' - '"sys.modules", the cache of all modules that have been imported\n' - 'previously. If the module is found there then it is used in step ' - '(2)\n' - 'of import.\n' - '\n' - 'If the module is not found in the cache, then "sys.meta_path" is\n' - 'searched (the specification for "sys.meta_path" can be found in ' - '**PEP\n' - '302**). The object is a list of *finder* objects which are queried ' - 'in\n' - 'order as to whether they know how to load the module by calling ' - 'their\n' - '"find_module()" method with the name of the module. If the module\n' - 'happens to be contained within a package (as denoted by the ' - 'existence\n' - 'of a dot in the name), then a second argument to "find_module()" ' - 'is\n' - 'given as the value of the "__path__" attribute from the parent ' - 'package\n' - '(everything up to the last dot in the name of the module being\n' - 'imported). If a finder can find the module it returns a *loader*\n' - '(discussed later) or returns "None".\n' - '\n' - 'If none of the finders on "sys.meta_path" are able to find the ' - 'module\n' - 'then some implicitly defined finders are queried. Implementations ' - 'of\n' - 'Python vary in what implicit meta path finders are defined. The ' - 'one\n' - 'they all do define, though, is one that handles "sys.path_hooks",\n' - '"sys.path_importer_cache", and "sys.path".\n' - '\n' - 'The implicit finder searches for the requested module in the ' - '"paths"\n' - 'specified in one of two places ("paths" do not have to be file ' - 'system\n' - 'paths). If the module being imported is supposed to be contained\n' - 'within a package then the second argument passed to ' - '"find_module()",\n' - '"__path__" on the parent package, is used as the source of paths. ' - 'If\n' - 'the module is not contained in a package then "sys.path" is used ' - 'as\n' - 'the source of paths.\n' - '\n' - 'Once the source of paths is chosen it is iterated over to find a\n' - 'finder that can handle that path. The dict at\n' - '"sys.path_importer_cache" caches finders for paths and is checked ' - 'for\n' - 'a finder. If the path does not have a finder cached then\n' - '"sys.path_hooks" is searched by calling each object in the list ' - 'with a\n' - 'single argument of the path, returning a finder or raises\n' - '"ImportError". If a finder is returned then it is cached in\n' - '"sys.path_importer_cache" and then used for that path entry. If ' - 'no\n' - 'finder can be found but the path exists then a value of "None" is\n' - 'stored in "sys.path_importer_cache" to signify that an implicit, ' - 'file-\n' - 'based finder that handles modules stored as individual files ' - 'should be\n' - 'used for that path. If the path does not exist then a finder ' - 'which\n' - 'always returns "None" is placed in the cache for the path.\n' - '\n' - 'If no finder can find the module then "ImportError" is raised.\n' - 'Otherwise some finder returned a loader whose "load_module()" ' - 'method\n' - 'is called with the name of the module to load (see **PEP 302** for ' - 'the\n' - 'original definition of loaders). A loader has several ' - 'responsibilities\n' - 'to perform on a module it loads. First, if the module already ' - 'exists\n' - 'in "sys.modules" (a possibility if the loader is called outside of ' - 'the\n' - 'import machinery) then it is to use that module for initialization ' - 'and\n' - 'not a new module. But if the module does not exist in ' - '"sys.modules"\n' - 'then it is to be added to that dict before initialization begins. ' - 'If\n' - 'an error occurs during loading of the module and it was added to\n' - '"sys.modules" it is to be removed from the dict. If an error ' - 'occurs\n' - 'but the module was already in "sys.modules" it is left in the ' - 'dict.\n' - '\n' - 'The loader must set several attributes on the module. "__name__" ' - 'is to\n' - 'be set to the name of the module. "__file__" is to be the "path" ' - 'to\n' - 'the file unless the module is built-in (and thus listed in\n' - '"sys.builtin_module_names") in which case the attribute is not ' - 'set. If\n' - 'what is being imported is a package then "__path__" is to be set ' - 'to a\n' - 'list of paths to be searched when looking for modules and ' - 'packages\n' - 'contained within the package being imported. "__package__" is ' - 'optional\n' - 'but should be set to the name of package that contains the module ' - 'or\n' - 'package (the empty string is used for module not contained in a\n' - 'package). "__loader__" is also optional but should be set to the\n' - 'loader object that is loading the module.\n' - '\n' - 'If an error occurs during loading then the loader raises ' - '"ImportError"\n' - 'if some other exception is not already being propagated. Otherwise ' - 'the\n' - 'loader returns the module that was loaded and initialized.\n' - '\n' - 'When step (1) finishes without raising an exception, step (2) can\n' - 'begin.\n' - '\n' - 'The first form of "import" statement binds the module name in the\n' - 'local namespace to the module object, and then goes on to import ' - 'the\n' - 'next identifier, if any. If the module name is followed by "as", ' - 'the\n' - 'name following "as" is used as the local name for the module.\n' - '\n' - 'The "from" form does not bind the module name: it goes through ' - 'the\n' - 'list of identifiers, looks each one of them up in the module found ' - 'in\n' - 'step (1), and binds the name in the local namespace to the object ' - 'thus\n' - 'found. As with the first form of "import", an alternate local ' - 'name\n' - 'can be supplied by specifying ""as" localname". If a name is not\n' - 'found, "ImportError" is raised. If the list of identifiers is\n' - 'replaced by a star ("\'*\'"), all public names defined in the ' - 'module are\n' - 'bound in the local namespace of the "import" statement..\n' - '\n' - 'The *public names* defined by a module are determined by checking ' - 'the\n' - 'module\'s namespace for a variable named "__all__"; if defined, it ' - 'must\n' - 'be a sequence of strings which are names defined or imported by ' - 'that\n' - 'module. The names given in "__all__" are all considered public ' - 'and\n' - 'are required to exist. If "__all__" is not defined, the set of ' - 'public\n' - "names includes all names found in the module's namespace which do " - 'not\n' - 'begin with an underscore character ("\'_\'"). "__all__" should ' - 'contain\n' - 'the entire public API. It is intended to avoid accidentally ' - 'exporting\n' - 'items that are not part of the API (such as library modules which ' - 'were\n' - 'imported and used within the module).\n' - '\n' - 'The "from" form with "*" may only occur in a module scope. If ' - 'the\n' - 'wild card form of import --- "import *" --- is used in a function ' - 'and\n' - 'the function contains or is a nested block with free variables, ' - 'the\n' - 'compiler will raise a "SyntaxError".\n' - '\n' - 'When specifying what module to import you do not have to specify ' - 'the\n' - 'absolute name of the module. When a module or package is ' - 'contained\n' - 'within another package it is possible to make a relative import ' - 'within\n' - 'the same top package without having to mention the package name. ' - 'By\n' - 'using leading dots in the specified module or package after "from" ' - 'you\n' - 'can specify how high to traverse up the current package hierarchy\n' - 'without specifying exact names. One leading dot means the current\n' - 'package where the module making the import exists. Two dots means ' - 'up\n' - 'one package level. Three dots is up two levels, etc. So if you ' - 'execute\n' - '"from . import mod" from a module in the "pkg" package then you ' - 'will\n' - 'end up importing "pkg.mod". If you execute "from ..subpkg2 import ' - 'mod"\n' - 'from within "pkg.subpkg1" you will import "pkg.subpkg2.mod". The\n' - 'specification for relative imports is contained within **PEP ' - '328**.\n' - '\n' - '"importlib.import_module()" is provided to support applications ' - 'that\n' - 'determine which modules need to be loaded dynamically.\n' - '\n' - '\n' - 'Future statements\n' - '=================\n' - '\n' - 'A *future statement* is a directive to the compiler that a ' - 'particular\n' - 'module should be compiled using syntax or semantics that will be\n' - 'available in a specified future release of Python. The future\n' - 'statement is intended to ease migration to future versions of ' - 'Python\n' - 'that introduce incompatible changes to the language. It allows ' - 'use of\n' - 'the new features on a per-module basis before the release in which ' - 'the\n' - 'feature becomes standard.\n' - '\n' - ' future_statement ::= "from" "__future__" "import" feature ["as" ' - 'name]\n' - ' ("," feature ["as" name])*\n' - ' | "from" "__future__" "import" "(" feature ' - '["as" name]\n' - ' ("," feature ["as" name])* [","] ")"\n' - ' feature ::= identifier\n' - ' name ::= identifier\n' - '\n' - 'A future statement must appear near the top of the module. The ' - 'only\n' - 'lines that can appear before a future statement are:\n' - '\n' - '* the module docstring (if any),\n' - '\n' - '* comments,\n' - '\n' - '* blank lines, and\n' - '\n' - '* other future statements.\n' - '\n' - 'The features recognized by Python 2.6 are "unicode_literals",\n' - '"print_function", "absolute_import", "division", "generators",\n' - '"nested_scopes" and "with_statement". "generators", ' - '"with_statement",\n' - '"nested_scopes" are redundant in Python version 2.6 and above ' - 'because\n' - 'they are always enabled.\n' - '\n' - 'A future statement is recognized and treated specially at compile\n' - 'time: Changes to the semantics of core constructs are often\n' - 'implemented by generating different code. It may even be the ' - 'case\n' - 'that a new feature introduces new incompatible syntax (such as a ' - 'new\n' - 'reserved word), in which case the compiler may need to parse the\n' - 'module differently. Such decisions cannot be pushed off until\n' - 'runtime.\n' - '\n' - 'For any given release, the compiler knows which feature names ' - 'have\n' - 'been defined, and raises a compile-time error if a future ' - 'statement\n' - 'contains a feature not known to it.\n' - '\n' - 'The direct runtime semantics are the same as for any import ' - 'statement:\n' - 'there is a standard module "__future__", described later, and it ' - 'will\n' - 'be imported in the usual way at the time the future statement is\n' - 'executed.\n' - '\n' - 'The interesting runtime semantics depend on the specific feature\n' - 'enabled by the future statement.\n' - '\n' - 'Note that there is nothing special about the statement:\n' - '\n' - ' import __future__ [as name]\n' - '\n' - "That is not a future statement; it's an ordinary import statement " - 'with\n' - 'no special semantics or syntax restrictions.\n' - '\n' - 'Code compiled by an "exec" statement or calls to the built-in\n' - 'functions "compile()" and "execfile()" that occur in a module "M"\n' - 'containing a future statement will, by default, use the new ' - 'syntax or\n' - 'semantics associated with the future statement. This can, ' - 'starting\n' - 'with Python 2.2 be controlled by optional arguments to "compile()" ' - '---\n' - 'see the documentation of that function for details.\n' - '\n' - 'A future statement typed at an interactive interpreter prompt ' - 'will\n' - 'take effect for the rest of the interpreter session. If an\n' - 'interpreter is started with the "-i" option, is passed a script ' - 'name\n' - 'to execute, and the script includes a future statement, it will be ' - 'in\n' - 'effect in the interactive session started after the script is\n' - 'executed.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 236** - Back to the __future__\n' - ' The original proposal for the __future__ mechanism.\n', - 'in': '\n' - 'Membership test operations\n' - '**************************\n' - '\n' - 'The operators "in" and "not in" test for membership. "x in s"\n' - 'evaluates to "True" if *x* is a member of *s*, and "False" otherwise.\n' - '"x not in s" returns the negation of "x in s". All built-in ' - 'sequences\n' - 'and set types support this as well as dictionary, for which "in" ' - 'tests\n' - 'whether the dictionary has a given key. For container types such as\n' - 'list, tuple, set, frozenset, dict, or collections.deque, the\n' - 'expression "x in y" is equivalent to "any(x is e or x == e for e in\n' - 'y)".\n' - '\n' - 'For the string and bytes types, "x in y" is "True" if and only if *x*\n' - 'is a substring of *y*. An equivalent test is "y.find(x) != -1".\n' - 'Empty strings are always considered to be a substring of any other\n' - 'string, so """ in "abc"" will return "True".\n' - '\n' - 'For user-defined classes which define the "__contains__()" method, "x\n' - 'in y" returns "True" if "y.__contains__(x)" returns a true value, and\n' - '"False" otherwise.\n' - '\n' - 'For user-defined classes which do not define "__contains__()" but do\n' - 'define "__iter__()", "x in y" is "True" if some value "z" with "x ==\n' - 'z" is produced while iterating over "y". If an exception is raised\n' - 'during the iteration, it is as if "in" raised that exception.\n' - '\n' - 'Lastly, the old-style iteration protocol is tried: if a class defines\n' - '"__getitem__()", "x in y" is "True" if and only if there is a non-\n' - 'negative integer index *i* such that "x == y[i]", and all lower\n' - 'integer indices do not raise "IndexError" exception. (If any other\n' - 'exception is raised, it is as if "in" raised that exception).\n' - '\n' - 'The operator "not in" is defined to have the inverse true value of\n' - '"in".\n', - 'integers': '\n' - 'Integer and long integer literals\n' - '*********************************\n' - '\n' - 'Integer and long integer literals are described by the ' - 'following\n' - 'lexical definitions:\n' - '\n' - ' longinteger ::= integer ("l" | "L")\n' - ' integer ::= decimalinteger | octinteger | hexinteger | ' - 'bininteger\n' - ' decimalinteger ::= nonzerodigit digit* | "0"\n' - ' octinteger ::= "0" ("o" | "O") octdigit+ | "0" octdigit+\n' - ' hexinteger ::= "0" ("x" | "X") hexdigit+\n' - ' bininteger ::= "0" ("b" | "B") bindigit+\n' - ' nonzerodigit ::= "1"..."9"\n' - ' octdigit ::= "0"..."7"\n' - ' bindigit ::= "0" | "1"\n' - ' hexdigit ::= digit | "a"..."f" | "A"..."F"\n' - '\n' - 'Although both lower case "\'l\'" and upper case "\'L\'" are ' - 'allowed as\n' - 'suffix for long integers, it is strongly recommended to always ' - 'use\n' - '"\'L\'", since the letter "\'l\'" looks too much like the digit ' - '"\'1\'".\n' - '\n' - 'Plain integer literals that are above the largest representable ' - 'plain\n' - 'integer (e.g., 2147483647 when using 32-bit arithmetic) are ' - 'accepted\n' - 'as if they were long integers instead. [1] There is no limit ' - 'for long\n' - 'integer literals apart from what can be stored in available ' - 'memory.\n' - '\n' - 'Some examples of plain integer literals (first row) and long ' - 'integer\n' - 'literals (second and third rows):\n' - '\n' - ' 7 2147483647 0177\n' - ' 3L 79228162514264337593543950336L 0377L 0x100000000L\n' - ' 79228162514264337593543950336 0xdeadbeef\n', - 'lambda': '\n' - 'Lambdas\n' - '*******\n' - '\n' - ' lambda_expr ::= "lambda" [parameter_list]: expression\n' - ' old_lambda_expr ::= "lambda" [parameter_list]: old_expression\n' - '\n' - 'Lambda expressions (sometimes called lambda forms) have the same\n' - 'syntactic position as expressions. They are a shorthand to ' - 'create\n' - 'anonymous functions; the expression "lambda arguments: ' - 'expression"\n' - 'yields a function object. The unnamed object behaves like a ' - 'function\n' - 'object defined with\n' - '\n' - ' def name(arguments):\n' - ' return expression\n' - '\n' - 'See section Function definitions for the syntax of parameter ' - 'lists.\n' - 'Note that functions created with lambda expressions cannot ' - 'contain\n' - 'statements.\n', - 'lists': '\n' - 'List displays\n' - '*************\n' - '\n' - 'A list display is a possibly empty series of expressions enclosed ' - 'in\n' - 'square brackets:\n' - '\n' - ' list_display ::= "[" [expression_list | ' - 'list_comprehension] "]"\n' - ' list_comprehension ::= expression list_for\n' - ' list_for ::= "for" target_list "in" ' - 'old_expression_list [list_iter]\n' - ' old_expression_list ::= old_expression [("," old_expression)+ ' - '[","]]\n' - ' old_expression ::= or_test | old_lambda_expr\n' - ' list_iter ::= list_for | list_if\n' - ' list_if ::= "if" old_expression [list_iter]\n' - '\n' - 'A list display yields a new list object. Its contents are ' - 'specified\n' - 'by providing either a list of expressions or a list comprehension.\n' - 'When a comma-separated list of expressions is supplied, its ' - 'elements\n' - 'are evaluated from left to right and placed into the list object ' - 'in\n' - 'that order. When a list comprehension is supplied, it consists of ' - 'a\n' - 'single expression followed by at least one "for" clause and zero ' - 'or\n' - 'more "for" or "if" clauses. In this case, the elements of the new\n' - 'list are those that would be produced by considering each of the ' - '"for"\n' - 'or "if" clauses a block, nesting from left to right, and ' - 'evaluating\n' - 'the expression to produce a list element each time the innermost ' - 'block\n' - 'is reached [1].\n', - 'naming': '\n' - 'Naming and binding\n' - '******************\n' - '\n' - '*Names* refer to objects. Names are introduced by name binding\n' - 'operations. Each occurrence of a name in the program text refers ' - 'to\n' - 'the *binding* of that name established in the innermost function ' - 'block\n' - 'containing the use.\n' - '\n' - 'A *block* is a piece of Python program text that is executed as a\n' - 'unit. The following are blocks: a module, a function body, and a ' - 'class\n' - 'definition. Each command typed interactively is a block. A ' - 'script\n' - 'file (a file given as standard input to the interpreter or ' - 'specified\n' - 'on the interpreter command line the first argument) is a code ' - 'block.\n' - 'A script command (a command specified on the interpreter command ' - 'line\n' - "with the '**-c**' option) is a code block. The file read by the\n" - 'built-in function "execfile()" is a code block. The string ' - 'argument\n' - 'passed to the built-in function "eval()" and to the "exec" ' - 'statement\n' - 'is a code block. The expression read and evaluated by the ' - 'built-in\n' - 'function "input()" is a code block.\n' - '\n' - 'A code block is executed in an *execution frame*. A frame ' - 'contains\n' - 'some administrative information (used for debugging) and ' - 'determines\n' - "where and how execution continues after the code block's execution " - 'has\n' - 'completed.\n' - '\n' - 'A *scope* defines the visibility of a name within a block. If a ' - 'local\n' - 'variable is defined in a block, its scope includes that block. If ' - 'the\n' - 'definition occurs in a function block, the scope extends to any ' - 'blocks\n' - 'contained within the defining one, unless a contained block ' - 'introduces\n' - 'a different binding for the name. The scope of names defined in ' - 'a\n' - 'class block is limited to the class block; it does not extend to ' - 'the\n' - 'code blocks of methods -- this includes generator expressions ' - 'since\n' - 'they are implemented using a function scope. This means that the\n' - 'following will fail:\n' - '\n' - ' class A:\n' - ' a = 42\n' - ' b = list(a + i for i in range(10))\n' - '\n' - 'When a name is used in a code block, it is resolved using the ' - 'nearest\n' - 'enclosing scope. The set of all such scopes visible to a code ' - 'block\n' - "is called the block's *environment*.\n" - '\n' - 'If a name is bound in a block, it is a local variable of that ' - 'block.\n' - 'If a name is bound at the module level, it is a global variable. ' - '(The\n' - 'variables of the module code block are local and global.) If a\n' - 'variable is used in a code block but not defined there, it is a ' - '*free\n' - 'variable*.\n' - '\n' - 'When a name is not found at all, a "NameError" exception is ' - 'raised.\n' - 'If the name refers to a local variable that has not been bound, a\n' - '"UnboundLocalError" exception is raised. "UnboundLocalError" is ' - 'a\n' - 'subclass of "NameError".\n' - '\n' - 'The following constructs bind names: formal parameters to ' - 'functions,\n' - '"import" statements, class and function definitions (these bind ' - 'the\n' - 'class or function name in the defining block), and targets that ' - 'are\n' - 'identifiers if occurring in an assignment, "for" loop header, in ' - 'the\n' - 'second position of an "except" clause header or after "as" in a ' - '"with"\n' - 'statement. The "import" statement of the form "from ... import ' - '*"\n' - 'binds all names defined in the imported module, except those ' - 'beginning\n' - 'with an underscore. This form may only be used at the module ' - 'level.\n' - '\n' - 'A target occurring in a "del" statement is also considered bound ' - 'for\n' - 'this purpose (though the actual semantics are to unbind the ' - 'name). It\n' - 'is illegal to unbind a name that is referenced by an enclosing ' - 'scope;\n' - 'the compiler will report a "SyntaxError".\n' - '\n' - 'Each assignment or import statement occurs within a block defined ' - 'by a\n' - 'class or function definition or at the module level (the ' - 'top-level\n' - 'code block).\n' - '\n' - 'If a name binding operation occurs anywhere within a code block, ' - 'all\n' - 'uses of the name within the block are treated as references to ' - 'the\n' - 'current block. This can lead to errors when a name is used within ' - 'a\n' - 'block before it is bound. This rule is subtle. Python lacks\n' - 'declarations and allows name binding operations to occur anywhere\n' - 'within a code block. The local variables of a code block can be\n' - 'determined by scanning the entire text of the block for name ' - 'binding\n' - 'operations.\n' - '\n' - 'If the global statement occurs within a block, all uses of the ' - 'name\n' - 'specified in the statement refer to the binding of that name in ' - 'the\n' - 'top-level namespace. Names are resolved in the top-level namespace ' - 'by\n' - 'searching the global namespace, i.e. the namespace of the module\n' - 'containing the code block, and the builtins namespace, the ' - 'namespace\n' - 'of the module "__builtin__". The global namespace is searched ' - 'first.\n' - 'If the name is not found there, the builtins namespace is ' - 'searched.\n' - 'The global statement must precede all uses of the name.\n' - '\n' - 'The builtins namespace associated with the execution of a code ' - 'block\n' - 'is actually found by looking up the name "__builtins__" in its ' - 'global\n' - 'namespace; this should be a dictionary or a module (in the latter ' - 'case\n' - "the module's dictionary is used). By default, when in the " - '"__main__"\n' - 'module, "__builtins__" is the built-in module "__builtin__" (note: ' - 'no\n' - '\'s\'); when in any other module, "__builtins__" is an alias for ' - 'the\n' - 'dictionary of the "__builtin__" module itself. "__builtins__" can ' - 'be\n' - 'set to a user-created dictionary to create a weak form of ' - 'restricted\n' - 'execution.\n' - '\n' - '**CPython implementation detail:** Users should not touch\n' - '"__builtins__"; it is strictly an implementation detail. Users\n' - 'wanting to override values in the builtins namespace should ' - '"import"\n' - 'the "__builtin__" (no \'s\') module and modify its attributes\n' - 'appropriately.\n' - '\n' - 'The namespace for a module is automatically created the first time ' - 'a\n' - 'module is imported. The main module for a script is always ' - 'called\n' - '"__main__".\n' - '\n' - 'The "global" statement has the same scope as a name binding ' - 'operation\n' - 'in the same block. If the nearest enclosing scope for a free ' - 'variable\n' - 'contains a global statement, the free variable is treated as a ' - 'global.\n' - '\n' - 'A class definition is an executable statement that may use and ' - 'define\n' - 'names. These references follow the normal rules for name ' - 'resolution.\n' - 'The namespace of the class definition becomes the attribute ' - 'dictionary\n' - 'of the class. Names defined at the class scope are not visible ' - 'in\n' - 'methods.\n' - '\n' - '\n' - 'Interaction with dynamic features\n' - '=================================\n' - '\n' - 'There are several cases where Python statements are illegal when ' - 'used\n' - 'in conjunction with nested scopes that contain free variables.\n' - '\n' - 'If a variable is referenced in an enclosing scope, it is illegal ' - 'to\n' - 'delete the name. An error will be reported at compile time.\n' - '\n' - 'If the wild card form of import --- "import *" --- is used in a\n' - 'function and the function contains or is a nested block with free\n' - 'variables, the compiler will raise a "SyntaxError".\n' - '\n' - 'If "exec" is used in a function and the function contains or is a\n' - 'nested block with free variables, the compiler will raise a\n' - '"SyntaxError" unless the exec explicitly specifies the local ' - 'namespace\n' - 'for the "exec". (In other words, "exec obj" would be illegal, ' - 'but\n' - '"exec obj in ns" would be legal.)\n' - '\n' - 'The "eval()", "execfile()", and "input()" functions and the ' - '"exec"\n' - 'statement do not have access to the full environment for ' - 'resolving\n' - 'names. Names may be resolved in the local and global namespaces ' - 'of\n' - 'the caller. Free variables are not resolved in the nearest ' - 'enclosing\n' - 'namespace, but in the global namespace. [1] The "exec" statement ' - 'and\n' - 'the "eval()" and "execfile()" functions have optional arguments ' - 'to\n' - 'override the global and local namespace. If only one namespace ' - 'is\n' - 'specified, it is used for both.\n', - 'numbers': '\n' - 'Numeric literals\n' - '****************\n' - '\n' - 'There are four types of numeric literals: plain integers, long\n' - 'integers, floating point numbers, and imaginary numbers. There ' - 'are no\n' - 'complex literals (complex numbers can be formed by adding a real\n' - 'number and an imaginary number).\n' - '\n' - 'Note that numeric literals do not include a sign; a phrase like ' - '"-1"\n' - 'is actually an expression composed of the unary operator \'"-"\' ' - 'and the\n' - 'literal "1".\n', - 'numeric-types': '\n' - 'Emulating numeric types\n' - '***********************\n' - '\n' - 'The following methods can be defined to emulate numeric ' - 'objects.\n' - 'Methods corresponding to operations that are not supported ' - 'by the\n' - 'particular kind of number implemented (e.g., bitwise ' - 'operations for\n' - 'non-integral numbers) should be left undefined.\n' - '\n' - 'object.__add__(self, other)\n' - 'object.__sub__(self, other)\n' - 'object.__mul__(self, other)\n' - 'object.__floordiv__(self, other)\n' - 'object.__mod__(self, other)\n' - 'object.__divmod__(self, other)\n' - 'object.__pow__(self, other[, modulo])\n' - 'object.__lshift__(self, other)\n' - 'object.__rshift__(self, other)\n' - 'object.__and__(self, other)\n' - 'object.__xor__(self, other)\n' - 'object.__or__(self, other)\n' - '\n' - ' These methods are called to implement the binary ' - 'arithmetic\n' - ' operations ("+", "-", "*", "//", "%", "divmod()", ' - '"pow()", "**",\n' - ' "<<", ">>", "&", "^", "|"). For instance, to evaluate ' - 'the\n' - ' expression "x + y", where *x* is an instance of a class ' - 'that has an\n' - ' "__add__()" method, "x.__add__(y)" is called. The ' - '"__divmod__()"\n' - ' method should be the equivalent to using ' - '"__floordiv__()" and\n' - ' "__mod__()"; it should not be related to "__truediv__()" ' - '(described\n' - ' below). Note that "__pow__()" should be defined to ' - 'accept an\n' - ' optional third argument if the ternary version of the ' - 'built-in\n' - ' "pow()" function is to be supported.\n' - '\n' - ' If one of those methods does not support the operation ' - 'with the\n' - ' supplied arguments, it should return "NotImplemented".\n' - '\n' - 'object.__div__(self, other)\n' - 'object.__truediv__(self, other)\n' - '\n' - ' The division operator ("/") is implemented by these ' - 'methods. The\n' - ' "__truediv__()" method is used when ' - '"__future__.division" is in\n' - ' effect, otherwise "__div__()" is used. If only one of ' - 'these two\n' - ' methods is defined, the object will not support division ' - 'in the\n' - ' alternate context; "TypeError" will be raised instead.\n' - '\n' - 'object.__radd__(self, other)\n' - 'object.__rsub__(self, other)\n' - 'object.__rmul__(self, other)\n' - 'object.__rdiv__(self, other)\n' - 'object.__rtruediv__(self, other)\n' - 'object.__rfloordiv__(self, other)\n' - 'object.__rmod__(self, other)\n' - 'object.__rdivmod__(self, other)\n' - 'object.__rpow__(self, other)\n' - 'object.__rlshift__(self, other)\n' - 'object.__rrshift__(self, other)\n' - 'object.__rand__(self, other)\n' - 'object.__rxor__(self, other)\n' - 'object.__ror__(self, other)\n' - '\n' - ' These methods are called to implement the binary ' - 'arithmetic\n' - ' operations ("+", "-", "*", "/", "%", "divmod()", ' - '"pow()", "**",\n' - ' "<<", ">>", "&", "^", "|") with reflected (swapped) ' - 'operands.\n' - ' These functions are only called if the left operand does ' - 'not\n' - ' support the corresponding operation and the operands are ' - 'of\n' - ' different types. [2] For instance, to evaluate the ' - 'expression "x -\n' - ' y", where *y* is an instance of a class that has an ' - '"__rsub__()"\n' - ' method, "y.__rsub__(x)" is called if "x.__sub__(y)" ' - 'returns\n' - ' *NotImplemented*.\n' - '\n' - ' Note that ternary "pow()" will not try calling ' - '"__rpow__()" (the\n' - ' coercion rules would become too complicated).\n' - '\n' - " Note: If the right operand's type is a subclass of the " - 'left\n' - " operand's type and that subclass provides the " - 'reflected method\n' - ' for the operation, this method will be called before ' - 'the left\n' - " operand's non-reflected method. This behavior allows " - 'subclasses\n' - " to override their ancestors' operations.\n" - '\n' - 'object.__iadd__(self, other)\n' - 'object.__isub__(self, other)\n' - 'object.__imul__(self, other)\n' - 'object.__idiv__(self, other)\n' - 'object.__itruediv__(self, other)\n' - 'object.__ifloordiv__(self, other)\n' - 'object.__imod__(self, other)\n' - 'object.__ipow__(self, other[, modulo])\n' - 'object.__ilshift__(self, other)\n' - 'object.__irshift__(self, other)\n' - 'object.__iand__(self, other)\n' - 'object.__ixor__(self, other)\n' - 'object.__ior__(self, other)\n' - '\n' - ' These methods are called to implement the augmented ' - 'arithmetic\n' - ' assignments ("+=", "-=", "*=", "/=", "//=", "%=", "**=", ' - '"<<=",\n' - ' ">>=", "&=", "^=", "|="). These methods should attempt ' - 'to do the\n' - ' operation in-place (modifying *self*) and return the ' - 'result (which\n' - ' could be, but does not have to be, *self*). If a ' - 'specific method\n' - ' is not defined, the augmented assignment falls back to ' - 'the normal\n' - ' methods. For instance, to execute the statement "x += ' - 'y", where\n' - ' *x* is an instance of a class that has an "__iadd__()" ' - 'method,\n' - ' "x.__iadd__(y)" is called. If *x* is an instance of a ' - 'class that\n' - ' does not define a "__iadd__()" method, "x.__add__(y)" ' - 'and\n' - ' "y.__radd__(x)" are considered, as with the evaluation ' - 'of "x + y".\n' - '\n' - 'object.__neg__(self)\n' - 'object.__pos__(self)\n' - 'object.__abs__(self)\n' - 'object.__invert__(self)\n' - '\n' - ' Called to implement the unary arithmetic operations ' - '("-", "+",\n' - ' "abs()" and "~").\n' - '\n' - 'object.__complex__(self)\n' - 'object.__int__(self)\n' - 'object.__long__(self)\n' - 'object.__float__(self)\n' - '\n' - ' Called to implement the built-in functions "complex()", ' - '"int()",\n' - ' "long()", and "float()". Should return a value of the ' - 'appropriate\n' - ' type.\n' - '\n' - 'object.__oct__(self)\n' - 'object.__hex__(self)\n' - '\n' - ' Called to implement the built-in functions "oct()" and ' - '"hex()".\n' - ' Should return a string value.\n' - '\n' - 'object.__index__(self)\n' - '\n' - ' Called to implement "operator.index()". Also called ' - 'whenever\n' - ' Python needs an integer object (such as in slicing). ' - 'Must return\n' - ' an integer (int or long).\n' - '\n' - ' New in version 2.5.\n' - '\n' - 'object.__coerce__(self, other)\n' - '\n' - ' Called to implement "mixed-mode" numeric arithmetic. ' - 'Should either\n' - ' return a 2-tuple containing *self* and *other* converted ' - 'to a\n' - ' common numeric type, or "None" if conversion is ' - 'impossible. When\n' - ' the common type would be the type of "other", it is ' - 'sufficient to\n' - ' return "None", since the interpreter will also ask the ' - 'other object\n' - ' to attempt a coercion (but sometimes, if the ' - 'implementation of the\n' - ' other type cannot be changed, it is useful to do the ' - 'conversion to\n' - ' the other type here). A return value of ' - '"NotImplemented" is\n' - ' equivalent to returning "None".\n', - 'objects': '\n' - 'Objects, values and types\n' - '*************************\n' - '\n' - "*Objects* are Python's abstraction for data. All data in a " - 'Python\n' - 'program is represented by objects or by relations between ' - 'objects. (In\n' - 'a sense, and in conformance to Von Neumann\'s model of a "stored\n' - 'program computer," code is also represented by objects.)\n' - '\n' - "Every object has an identity, a type and a value. An object's\n" - '*identity* never changes once it has been created; you may think ' - 'of it\n' - 'as the object\'s address in memory. The \'"is"\' operator ' - 'compares the\n' - 'identity of two objects; the "id()" function returns an integer\n' - 'representing its identity (currently implemented as its address). ' - 'An\n' - "object's *type* is also unchangeable. [1] An object's type " - 'determines\n' - 'the operations that the object supports (e.g., "does it have a\n' - 'length?") and also defines the possible values for objects of ' - 'that\n' - 'type. The "type()" function returns an object\'s type (which is ' - 'an\n' - 'object itself). The *value* of some objects can change. ' - 'Objects\n' - 'whose value can change are said to be *mutable*; objects whose ' - 'value\n' - 'is unchangeable once they are created are called *immutable*. ' - '(The\n' - 'value of an immutable container object that contains a reference ' - 'to a\n' - "mutable object can change when the latter's value is changed; " - 'however\n' - 'the container is still considered immutable, because the ' - 'collection of\n' - 'objects it contains cannot be changed. So, immutability is not\n' - 'strictly the same as having an unchangeable value, it is more ' - 'subtle.)\n' - "An object's mutability is determined by its type; for instance,\n" - 'numbers, strings and tuples are immutable, while dictionaries ' - 'and\n' - 'lists are mutable.\n' - '\n' - 'Objects are never explicitly destroyed; however, when they ' - 'become\n' - 'unreachable they may be garbage-collected. An implementation is\n' - 'allowed to postpone garbage collection or omit it altogether --- ' - 'it is\n' - 'a matter of implementation quality how garbage collection is\n' - 'implemented, as long as no objects are collected that are still\n' - 'reachable.\n' - '\n' - '**CPython implementation detail:** CPython currently uses a ' - 'reference-\n' - 'counting scheme with (optional) delayed detection of cyclically ' - 'linked\n' - 'garbage, which collects most objects as soon as they become\n' - 'unreachable, but is not guaranteed to collect garbage containing\n' - 'circular references. See the documentation of the "gc" module ' - 'for\n' - 'information on controlling the collection of cyclic garbage. ' - 'Other\n' - 'implementations act differently and CPython may change. Do not ' - 'depend\n' - 'on immediate finalization of objects when they become unreachable ' - '(ex:\n' - 'always close files).\n' - '\n' - "Note that the use of the implementation's tracing or debugging\n" - 'facilities may keep objects alive that would normally be ' - 'collectable.\n' - 'Also note that catching an exception with a \'"try"..."except"\'\n' - 'statement may keep objects alive.\n' - '\n' - 'Some objects contain references to "external" resources such as ' - 'open\n' - 'files or windows. It is understood that these resources are ' - 'freed\n' - 'when the object is garbage-collected, but since garbage ' - 'collection is\n' - 'not guaranteed to happen, such objects also provide an explicit ' - 'way to\n' - 'release the external resource, usually a "close()" method. ' - 'Programs\n' - 'are strongly recommended to explicitly close such objects. The\n' - '\'"try"..."finally"\' statement provides a convenient way to do ' - 'this.\n' - '\n' - 'Some objects contain references to other objects; these are ' - 'called\n' - '*containers*. Examples of containers are tuples, lists and\n' - "dictionaries. The references are part of a container's value. " - 'In\n' - 'most cases, when we talk about the value of a container, we imply ' - 'the\n' - 'values, not the identities of the contained objects; however, ' - 'when we\n' - 'talk about the mutability of a container, only the identities of ' - 'the\n' - 'immediately contained objects are implied. So, if an immutable\n' - 'container (like a tuple) contains a reference to a mutable ' - 'object, its\n' - 'value changes if that mutable object is changed.\n' - '\n' - 'Types affect almost all aspects of object behavior. Even the\n' - 'importance of object identity is affected in some sense: for ' - 'immutable\n' - 'types, operations that compute new values may actually return a\n' - 'reference to any existing object with the same type and value, ' - 'while\n' - 'for mutable objects this is not allowed. E.g., after "a = 1; b = ' - '1",\n' - '"a" and "b" may or may not refer to the same object with the ' - 'value\n' - 'one, depending on the implementation, but after "c = []; d = []", ' - '"c"\n' - 'and "d" are guaranteed to refer to two different, unique, newly\n' - 'created empty lists. (Note that "c = d = []" assigns the same ' - 'object\n' - 'to both "c" and "d".)\n', - 'operator-summary': '\n' - 'Operator precedence\n' - '*******************\n' - '\n' - 'The following table summarizes the operator precedences ' - 'in Python,\n' - 'from lowest precedence (least binding) to highest ' - 'precedence (most\n' - 'binding). Operators in the same box have the same ' - 'precedence. Unless\n' - 'the syntax is explicitly given, operators are binary. ' - 'Operators in\n' - 'the same box group left to right (except for ' - 'comparisons, including\n' - 'tests, which all have the same precedence and chain from ' - 'left to right\n' - '--- see section Comparisons --- and exponentiation, ' - 'which groups from\n' - 'right to left).\n' - '\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| Operator | ' - 'Description |\n' - '+=================================================+=======================================+\n' - '| "lambda" | ' - 'Lambda expression |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "if" -- "else" | ' - 'Conditional expression |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "or" | ' - 'Boolean OR |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "and" | ' - 'Boolean AND |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "not" "x" | ' - 'Boolean NOT |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "in", "not in", "is", "is not", "<", "<=", ">", | ' - 'Comparisons, including membership |\n' - '| ">=", "<>", "!=", "==" | ' - 'tests and identity tests |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "|" | ' - 'Bitwise OR |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "^" | ' - 'Bitwise XOR |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "&" | ' - 'Bitwise AND |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "<<", ">>" | ' - 'Shifts |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "+", "-" | ' - 'Addition and subtraction |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "*", "/", "//", "%" | ' - 'Multiplication, division, remainder |\n' - '| | ' - '[7] |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "+x", "-x", "~x" | ' - 'Positive, negative, bitwise NOT |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "**" | ' - 'Exponentiation [8] |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "x[index]", "x[index:index]", | ' - 'Subscription, slicing, call, |\n' - '| "x(arguments...)", "x.attribute" | ' - 'attribute reference |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '| "(expressions...)", "[expressions...]", "{key: | ' - 'Binding or tuple display, list |\n' - '| value...}", "`expressions...`" | ' - 'display, dictionary display, string |\n' - '| | ' - 'conversion |\n' - '+-------------------------------------------------+---------------------------------------+\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] In Python 2.3 and later releases, a list ' - 'comprehension "leaks"\n' - ' the control variables of each "for" it contains into ' - 'the\n' - ' containing scope. However, this behavior is ' - 'deprecated, and\n' - ' relying on it will not work in Python 3.\n' - '\n' - '[2] While "abs(x%y) < abs(y)" is true mathematically, ' - 'for floats\n' - ' it may not be true numerically due to roundoff. For ' - 'example, and\n' - ' assuming a platform on which a Python float is an ' - 'IEEE 754 double-\n' - ' precision number, in order that "-1e-100 % 1e100" ' - 'have the same\n' - ' sign as "1e100", the computed result is "-1e-100 + ' - '1e100", which\n' - ' is numerically exactly equal to "1e100". The ' - 'function\n' - ' "math.fmod()" returns a result whose sign matches ' - 'the sign of the\n' - ' first argument instead, and so returns "-1e-100" in ' - 'this case.\n' - ' Which approach is more appropriate depends on the ' - 'application.\n' - '\n' - '[3] If x is very close to an exact integer multiple of ' - "y, it's\n" - ' possible for "floor(x/y)" to be one larger than ' - '"(x-x%y)/y" due to\n' - ' rounding. In such cases, Python returns the latter ' - 'result, in\n' - ' order to preserve that "divmod(x,y)[0] * y + x % y" ' - 'be very close\n' - ' to "x".\n' - '\n' - '[4] The Unicode standard distinguishes between *code ' - 'points* (e.g.\n' - ' U+0041) and *abstract characters* (e.g. "LATIN ' - 'CAPITAL LETTER A").\n' - ' While most abstract characters in Unicode are only ' - 'represented\n' - ' using one code point, there is a number of abstract ' - 'characters\n' - ' that can in addition be represented using a sequence ' - 'of more than\n' - ' one code point. For example, the abstract character ' - '"LATIN\n' - ' CAPITAL LETTER C WITH CEDILLA" can be represented as ' - 'a single\n' - ' *precomposed character* at code position U+00C7, or ' - 'as a sequence\n' - ' of a *base character* at code position U+0043 (LATIN ' - 'CAPITAL\n' - ' LETTER C), followed by a *combining character* at ' - 'code position\n' - ' U+0327 (COMBINING CEDILLA).\n' - '\n' - ' The comparison operators on unicode strings compare ' - 'at the level\n' - ' of Unicode code points. This may be ' - 'counter-intuitive to humans.\n' - ' For example, "u"\\u00C7" == u"\\u0043\\u0327"" is ' - '"False", even\n' - ' though both strings represent the same abstract ' - 'character "LATIN\n' - ' CAPITAL LETTER C WITH CEDILLA".\n' - '\n' - ' To compare strings at the level of abstract ' - 'characters (that is,\n' - ' in a way intuitive to humans), use ' - '"unicodedata.normalize()".\n' - '\n' - '[5] Earlier versions of Python used lexicographic ' - 'comparison of\n' - ' the sorted (key, value) lists, but this was very ' - 'expensive for the\n' - ' common case of comparing for equality. An even ' - 'earlier version of\n' - ' Python compared dictionaries by identity only, but ' - 'this caused\n' - ' surprises because people expected to be able to test ' - 'a dictionary\n' - ' for emptiness by comparing it to "{}".\n' - '\n' - '[6] Due to automatic garbage-collection, free lists, and ' - 'the\n' - ' dynamic nature of descriptors, you may notice ' - 'seemingly unusual\n' - ' behaviour in certain uses of the "is" operator, like ' - 'those\n' - ' involving comparisons between instance methods, or ' - 'constants.\n' - ' Check their documentation for more info.\n' - '\n' - '[7] The "%" operator is also used for string formatting; ' - 'the same\n' - ' precedence applies.\n' - '\n' - '[8] The power operator "**" binds less tightly than an ' - 'arithmetic\n' - ' or bitwise unary operator on its right, that is, ' - '"2**-1" is "0.5".\n', - 'pass': '\n' - 'The "pass" statement\n' - '********************\n' - '\n' - ' pass_stmt ::= "pass"\n' - '\n' - '"pass" is a null operation --- when it is executed, nothing ' - 'happens.\n' - 'It is useful as a placeholder when a statement is required\n' - 'syntactically, but no code needs to be executed, for example:\n' - '\n' - ' def f(arg): pass # a function that does nothing (yet)\n' - '\n' - ' class C: pass # a class with no methods (yet)\n', - 'power': '\n' - 'The power operator\n' - '******************\n' - '\n' - 'The power operator binds more tightly than unary operators on its\n' - 'left; it binds less tightly than unary operators on its right. ' - 'The\n' - 'syntax is:\n' - '\n' - ' power ::= primary ["**" u_expr]\n' - '\n' - 'Thus, in an unparenthesized sequence of power and unary operators, ' - 'the\n' - 'operators are evaluated from right to left (this does not ' - 'constrain\n' - 'the evaluation order for the operands): "-1**2" results in "-1".\n' - '\n' - 'The power operator has the same semantics as the built-in "pow()"\n' - 'function, when called with two arguments: it yields its left ' - 'argument\n' - 'raised to the power of its right argument. The numeric arguments ' - 'are\n' - 'first converted to a common type. The result type is that of the\n' - 'arguments after coercion.\n' - '\n' - 'With mixed operand types, the coercion rules for binary arithmetic\n' - 'operators apply. For int and long int operands, the result has the\n' - 'same type as the operands (after coercion) unless the second ' - 'argument\n' - 'is negative; in that case, all arguments are converted to float and ' - 'a\n' - 'float result is delivered. For example, "10**2" returns "100", but\n' - '"10**-2" returns "0.01". (This last feature was added in Python ' - '2.2.\n' - 'In Python 2.1 and before, if both arguments were of integer types ' - 'and\n' - 'the second argument was negative, an exception was raised).\n' - '\n' - 'Raising "0.0" to a negative power results in a ' - '"ZeroDivisionError".\n' - 'Raising a negative number to a fractional power results in a\n' - '"ValueError".\n', - 'print': '\n' - 'The "print" statement\n' - '*********************\n' - '\n' - ' print_stmt ::= "print" ([expression ("," expression)* [","]]\n' - ' | ">>" expression [("," expression)+ [","]])\n' - '\n' - '"print" evaluates each expression in turn and writes the resulting\n' - 'object to standard output (see below). If an object is not a ' - 'string,\n' - 'it is first converted to a string using the rules for string\n' - 'conversions. The (resulting or original) string is then written. ' - 'A\n' - 'space is written before each object is (converted and) written, ' - 'unless\n' - 'the output system believes it is positioned at the beginning of a\n' - 'line. This is the case (1) when no characters have yet been ' - 'written\n' - 'to standard output, (2) when the last character written to ' - 'standard\n' - 'output is a whitespace character except "\' \'", or (3) when the ' - 'last\n' - 'write operation on standard output was not a "print" statement. ' - '(In\n' - 'some cases it may be functional to write an empty string to ' - 'standard\n' - 'output for this reason.)\n' - '\n' - 'Note: Objects which act like file objects but which are not the\n' - ' built-in file objects often do not properly emulate this aspect ' - 'of\n' - " the file object's behavior, so it is best not to rely on this.\n" - '\n' - 'A "\'\\n\'" character is written at the end, unless the "print" ' - 'statement\n' - 'ends with a comma. This is the only action if the statement ' - 'contains\n' - 'just the keyword "print".\n' - '\n' - 'Standard output is defined as the file object named "stdout" in ' - 'the\n' - 'built-in module "sys". If no such object exists, or if it does ' - 'not\n' - 'have a "write()" method, a "RuntimeError" exception is raised.\n' - '\n' - '"print" also has an extended form, defined by the second portion ' - 'of\n' - 'the syntax described above. This form is sometimes referred to as\n' - '""print" chevron." In this form, the first expression after the ' - '">>"\n' - 'must evaluate to a "file-like" object, specifically an object that ' - 'has\n' - 'a "write()" method as described above. With this extended form, ' - 'the\n' - 'subsequent expressions are printed to this file object. If the ' - 'first\n' - 'expression evaluates to "None", then "sys.stdout" is used as the ' - 'file\n' - 'for output.\n', - 'raise': '\n' - 'The "raise" statement\n' - '*********************\n' - '\n' - ' raise_stmt ::= "raise" [expression ["," expression ["," ' - 'expression]]]\n' - '\n' - 'If no expressions are present, "raise" re-raises the last ' - 'exception\n' - 'that was active in the current scope. If no exception is active ' - 'in\n' - 'the current scope, a "TypeError" exception is raised indicating ' - 'that\n' - 'this is an error (if running under IDLE, a "Queue.Empty" exception ' - 'is\n' - 'raised instead).\n' - '\n' - 'Otherwise, "raise" evaluates the expressions to get three objects,\n' - 'using "None" as the value of omitted expressions. The first two\n' - 'objects are used to determine the *type* and *value* of the ' - 'exception.\n' - '\n' - 'If the first object is an instance, the type of the exception is ' - 'the\n' - 'class of the instance, the instance itself is the value, and the\n' - 'second object must be "None".\n' - '\n' - 'If the first object is a class, it becomes the type of the ' - 'exception.\n' - 'The second object is used to determine the exception value: If it ' - 'is\n' - 'an instance of the class, the instance becomes the exception value. ' - 'If\n' - 'the second object is a tuple, it is used as the argument list for ' - 'the\n' - 'class constructor; if it is "None", an empty argument list is ' - 'used,\n' - 'and any other object is treated as a single argument to the\n' - 'constructor. The instance so created by calling the constructor ' - 'is\n' - 'used as the exception value.\n' - '\n' - 'If a third object is present and not "None", it must be a ' - 'traceback\n' - 'object (see section The standard type hierarchy), and it is\n' - 'substituted instead of the current location as the place where the\n' - 'exception occurred. If the third object is present and not a\n' - 'traceback object or "None", a "TypeError" exception is raised. ' - 'The\n' - 'three-expression form of "raise" is useful to re-raise an ' - 'exception\n' - 'transparently in an except clause, but "raise" with no expressions\n' - 'should be preferred if the exception to be re-raised was the most\n' - 'recently active exception in the current scope.\n' - '\n' - 'Additional information on exceptions can be found in section\n' - 'Exceptions, and information about handling exceptions is in ' - 'section\n' - 'The try statement.\n', - 'return': '\n' - 'The "return" statement\n' - '**********************\n' - '\n' - ' return_stmt ::= "return" [expression_list]\n' - '\n' - '"return" may only occur syntactically nested in a function ' - 'definition,\n' - 'not within a nested class definition.\n' - '\n' - 'If an expression list is present, it is evaluated, else "None" is\n' - 'substituted.\n' - '\n' - '"return" leaves the current function call with the expression list ' - '(or\n' - '"None") as return value.\n' - '\n' - 'When "return" passes control out of a "try" statement with a ' - '"finally"\n' - 'clause, that "finally" clause is executed before really leaving ' - 'the\n' - 'function.\n' - '\n' - 'In a generator function, the "return" statement is not allowed to\n' - 'include an "expression_list". In that context, a bare "return"\n' - 'indicates that the generator is done and will cause ' - '"StopIteration" to\n' - 'be raised.\n', - 'sequence-types': '\n' - 'Emulating container types\n' - '*************************\n' - '\n' - 'The following methods can be defined to implement ' - 'container objects.\n' - 'Containers usually are sequences (such as lists or tuples) ' - 'or mappings\n' - '(like dictionaries), but can represent other containers as ' - 'well. The\n' - 'first set of methods is used either to emulate a sequence ' - 'or to\n' - 'emulate a mapping; the difference is that for a sequence, ' - 'the\n' - 'allowable keys should be the integers *k* for which "0 <= ' - 'k < N" where\n' - '*N* is the length of the sequence, or slice objects, which ' - 'define a\n' - 'range of items. (For backwards compatibility, the method\n' - '"__getslice__()" (see below) can also be defined to handle ' - 'simple, but\n' - 'not extended slices.) It is also recommended that mappings ' - 'provide the\n' - 'methods "keys()", "values()", "items()", "has_key()", ' - '"get()",\n' - '"clear()", "setdefault()", "iterkeys()", "itervalues()",\n' - '"iteritems()", "pop()", "popitem()", "copy()", and ' - '"update()" behaving\n' - "similar to those for Python's standard dictionary " - 'objects. The\n' - '"UserDict" module provides a "DictMixin" class to help ' - 'create those\n' - 'methods from a base set of "__getitem__()", ' - '"__setitem__()",\n' - '"__delitem__()", and "keys()". Mutable sequences should ' - 'provide\n' - 'methods "append()", "count()", "index()", "extend()", ' - '"insert()",\n' - '"pop()", "remove()", "reverse()" and "sort()", like Python ' - 'standard\n' - 'list objects. Finally, sequence types should implement ' - 'addition\n' - '(meaning concatenation) and multiplication (meaning ' - 'repetition) by\n' - 'defining the methods "__add__()", "__radd__()", ' - '"__iadd__()",\n' - '"__mul__()", "__rmul__()" and "__imul__()" described ' - 'below; they\n' - 'should not define "__coerce__()" or other numerical ' - 'operators. It is\n' - 'recommended that both mappings and sequences implement ' - 'the\n' - '"__contains__()" method to allow efficient use of the "in" ' - 'operator;\n' - 'for mappings, "in" should be equivalent of "has_key()"; ' - 'for sequences,\n' - 'it should search through the values. It is further ' - 'recommended that\n' - 'both mappings and sequences implement the "__iter__()" ' - 'method to allow\n' - 'efficient iteration through the container; for mappings, ' - '"__iter__()"\n' - 'should be the same as "iterkeys()"; for sequences, it ' - 'should iterate\n' - 'through the values.\n' - '\n' - 'object.__len__(self)\n' - '\n' - ' Called to implement the built-in function "len()". ' - 'Should return\n' - ' the length of the object, an integer ">=" 0. Also, an ' - 'object that\n' - ' doesn\'t define a "__nonzero__()" method and whose ' - '"__len__()"\n' - ' method returns zero is considered to be false in a ' - 'Boolean context.\n' - '\n' - ' **CPython implementation detail:** In CPython, the ' - 'length is\n' - ' required to be at most "sys.maxsize". If the length is ' - 'larger than\n' - ' "sys.maxsize" some features (such as "len()") may ' - 'raise\n' - ' "OverflowError". To prevent raising "OverflowError" by ' - 'truth value\n' - ' testing, an object must define a "__nonzero__()" ' - 'method.\n' - '\n' - 'object.__getitem__(self, key)\n' - '\n' - ' Called to implement evaluation of "self[key]". For ' - 'sequence types,\n' - ' the accepted keys should be integers and slice ' - 'objects. Note that\n' - ' the special interpretation of negative indexes (if the ' - 'class wishes\n' - ' to emulate a sequence type) is up to the ' - '"__getitem__()" method. If\n' - ' *key* is of an inappropriate type, "TypeError" may be ' - 'raised; if of\n' - ' a value outside the set of indexes for the sequence ' - '(after any\n' - ' special interpretation of negative values), ' - '"IndexError" should be\n' - ' raised. For mapping types, if *key* is missing (not in ' - 'the\n' - ' container), "KeyError" should be raised.\n' - '\n' - ' Note: "for" loops expect that an "IndexError" will be ' - 'raised for\n' - ' illegal indexes to allow proper detection of the end ' - 'of the\n' - ' sequence.\n' - '\n' - 'object.__missing__(self, key)\n' - '\n' - ' Called by "dict"."__getitem__()" to implement ' - '"self[key]" for dict\n' - ' subclasses when key is not in the dictionary.\n' - '\n' - 'object.__setitem__(self, key, value)\n' - '\n' - ' Called to implement assignment to "self[key]". Same ' - 'note as for\n' - ' "__getitem__()". This should only be implemented for ' - 'mappings if\n' - ' the objects support changes to the values for keys, or ' - 'if new keys\n' - ' can be added, or for sequences if elements can be ' - 'replaced. The\n' - ' same exceptions should be raised for improper *key* ' - 'values as for\n' - ' the "__getitem__()" method.\n' - '\n' - 'object.__delitem__(self, key)\n' - '\n' - ' Called to implement deletion of "self[key]". Same note ' - 'as for\n' - ' "__getitem__()". This should only be implemented for ' - 'mappings if\n' - ' the objects support removal of keys, or for sequences ' - 'if elements\n' - ' can be removed from the sequence. The same exceptions ' - 'should be\n' - ' raised for improper *key* values as for the ' - '"__getitem__()" method.\n' - '\n' - 'object.__iter__(self)\n' - '\n' - ' This method is called when an iterator is required for ' - 'a container.\n' - ' This method should return a new iterator object that ' - 'can iterate\n' - ' over all the objects in the container. For mappings, ' - 'it should\n' - ' iterate over the keys of the container, and should also ' - 'be made\n' - ' available as the method "iterkeys()".\n' - '\n' - ' Iterator objects also need to implement this method; ' - 'they are\n' - ' required to return themselves. For more information on ' - 'iterator\n' - ' objects, see Iterator Types.\n' - '\n' - 'object.__reversed__(self)\n' - '\n' - ' Called (if present) by the "reversed()" built-in to ' - 'implement\n' - ' reverse iteration. It should return a new iterator ' - 'object that\n' - ' iterates over all the objects in the container in ' - 'reverse order.\n' - '\n' - ' If the "__reversed__()" method is not provided, the ' - '"reversed()"\n' - ' built-in will fall back to using the sequence protocol ' - '("__len__()"\n' - ' and "__getitem__()"). Objects that support the ' - 'sequence protocol\n' - ' should only provide "__reversed__()" if they can ' - 'provide an\n' - ' implementation that is more efficient than the one ' - 'provided by\n' - ' "reversed()".\n' - '\n' - ' New in version 2.6.\n' - '\n' - 'The membership test operators ("in" and "not in") are ' - 'normally\n' - 'implemented as an iteration through a sequence. However, ' - 'container\n' - 'objects can supply the following special method with a ' - 'more efficient\n' - 'implementation, which also does not require the object be ' - 'a sequence.\n' - '\n' - 'object.__contains__(self, item)\n' - '\n' - ' Called to implement membership test operators. Should ' - 'return true\n' - ' if *item* is in *self*, false otherwise. For mapping ' - 'objects, this\n' - ' should consider the keys of the mapping rather than the ' - 'values or\n' - ' the key-item pairs.\n' - '\n' - ' For objects that don\'t define "__contains__()", the ' - 'membership test\n' - ' first tries iteration via "__iter__()", then the old ' - 'sequence\n' - ' iteration protocol via "__getitem__()", see this ' - 'section in the\n' - ' language reference.\n', - 'shifting': '\n' - 'Shifting operations\n' - '*******************\n' - '\n' - 'The shifting operations have lower priority than the arithmetic\n' - 'operations:\n' - '\n' - ' shift_expr ::= a_expr | shift_expr ( "<<" | ">>" ) a_expr\n' - '\n' - 'These operators accept plain or long integers as arguments. ' - 'The\n' - 'arguments are converted to a common type. They shift the first\n' - 'argument to the left or right by the number of bits given by ' - 'the\n' - 'second argument.\n' - '\n' - 'A right shift by *n* bits is defined as division by "pow(2, ' - 'n)". A\n' - 'left shift by *n* bits is defined as multiplication with "pow(2, ' - 'n)".\n' - 'Negative shift counts raise a "ValueError" exception.\n' - '\n' - 'Note: In the current implementation, the right-hand operand is\n' - ' required to be at most "sys.maxsize". If the right-hand ' - 'operand is\n' - ' larger than "sys.maxsize" an "OverflowError" exception is ' - 'raised.\n', - 'slicings': '\n' - 'Slicings\n' - '********\n' - '\n' - 'A slicing selects a range of items in a sequence object (e.g., ' - 'a\n' - 'string, tuple or list). Slicings may be used as expressions or ' - 'as\n' - 'targets in assignment or "del" statements. The syntax for a ' - 'slicing:\n' - '\n' - ' slicing ::= simple_slicing | extended_slicing\n' - ' simple_slicing ::= primary "[" short_slice "]"\n' - ' extended_slicing ::= primary "[" slice_list "]"\n' - ' slice_list ::= slice_item ("," slice_item)* [","]\n' - ' slice_item ::= expression | proper_slice | ellipsis\n' - ' proper_slice ::= short_slice | long_slice\n' - ' short_slice ::= [lower_bound] ":" [upper_bound]\n' - ' long_slice ::= short_slice ":" [stride]\n' - ' lower_bound ::= expression\n' - ' upper_bound ::= expression\n' - ' stride ::= expression\n' - ' ellipsis ::= "..."\n' - '\n' - 'There is ambiguity in the formal syntax here: anything that ' - 'looks like\n' - 'an expression list also looks like a slice list, so any ' - 'subscription\n' - 'can be interpreted as a slicing. Rather than further ' - 'complicating the\n' - 'syntax, this is disambiguated by defining that in this case the\n' - 'interpretation as a subscription takes priority over the\n' - 'interpretation as a slicing (this is the case if the slice list\n' - 'contains no proper slice nor ellipses). Similarly, when the ' - 'slice\n' - 'list has exactly one short slice and no trailing comma, the\n' - 'interpretation as a simple slicing takes priority over that as ' - 'an\n' - 'extended slicing.\n' - '\n' - 'The semantics for a simple slicing are as follows. The primary ' - 'must\n' - 'evaluate to a sequence object. The lower and upper bound ' - 'expressions,\n' - 'if present, must evaluate to plain integers; defaults are zero ' - 'and the\n' - '"sys.maxint", respectively. If either bound is negative, the\n' - "sequence's length is added to it. The slicing now selects all " - 'items\n' - 'with index *k* such that "i <= k < j" where *i* and *j* are the\n' - 'specified lower and upper bounds. This may be an empty ' - 'sequence. It\n' - 'is not an error if *i* or *j* lie outside the range of valid ' - 'indexes\n' - "(such items don't exist so they aren't selected).\n" - '\n' - 'The semantics for an extended slicing are as follows. The ' - 'primary\n' - 'must evaluate to a mapping object, and it is indexed with a key ' - 'that\n' - 'is constructed from the slice list, as follows. If the slice ' - 'list\n' - 'contains at least one comma, the key is a tuple containing the\n' - 'conversion of the slice items; otherwise, the conversion of the ' - 'lone\n' - 'slice item is the key. The conversion of a slice item that is ' - 'an\n' - 'expression is that expression. The conversion of an ellipsis ' - 'slice\n' - 'item is the built-in "Ellipsis" object. The conversion of a ' - 'proper\n' - 'slice is a slice object (see section The standard type ' - 'hierarchy)\n' - 'whose "start", "stop" and "step" attributes are the values of ' - 'the\n' - 'expressions given as lower bound, upper bound and stride,\n' - 'respectively, substituting "None" for missing expressions.\n', - 'specialattrs': '\n' - 'Special Attributes\n' - '******************\n' - '\n' - 'The implementation adds a few special read-only attributes ' - 'to several\n' - 'object types, where they are relevant. Some of these are ' - 'not reported\n' - 'by the "dir()" built-in function.\n' - '\n' - 'object.__dict__\n' - '\n' - ' A dictionary or other mapping object used to store an ' - "object's\n" - ' (writable) attributes.\n' - '\n' - 'object.__methods__\n' - '\n' - ' Deprecated since version 2.2: Use the built-in function ' - '"dir()" to\n' - " get a list of an object's attributes. This attribute is " - 'no longer\n' - ' available.\n' - '\n' - 'object.__members__\n' - '\n' - ' Deprecated since version 2.2: Use the built-in function ' - '"dir()" to\n' - " get a list of an object's attributes. This attribute is " - 'no longer\n' - ' available.\n' - '\n' - 'instance.__class__\n' - '\n' - ' The class to which a class instance belongs.\n' - '\n' - 'class.__bases__\n' - '\n' - ' The tuple of base classes of a class object.\n' - '\n' - 'definition.__name__\n' - '\n' - ' The name of the class, type, function, method, ' - 'descriptor, or\n' - ' generator instance.\n' - '\n' - 'The following attributes are only supported by *new-style ' - 'class*es.\n' - '\n' - 'class.__mro__\n' - '\n' - ' This attribute is a tuple of classes that are considered ' - 'when\n' - ' looking for base classes during method resolution.\n' - '\n' - 'class.mro()\n' - '\n' - ' This method can be overridden by a metaclass to customize ' - 'the\n' - ' method resolution order for its instances. It is called ' - 'at class\n' - ' instantiation, and its result is stored in "__mro__".\n' - '\n' - 'class.__subclasses__()\n' - '\n' - ' Each new-style class keeps a list of weak references to ' - 'its\n' - ' immediate subclasses. This method returns a list of all ' - 'those\n' - ' references still alive. Example:\n' - '\n' - ' >>> int.__subclasses__()\n' - " [<type 'bool'>]\n" - '\n' - '-[ Footnotes ]-\n' - '\n' - '[1] Additional information on these special methods may be ' - 'found\n' - ' in the Python Reference Manual (Basic customization).\n' - '\n' - '[2] As a consequence, the list "[1, 2]" is considered equal ' - 'to\n' - ' "[1.0, 2.0]", and similarly for tuples.\n' - '\n' - "[3] They must have since the parser can't tell the type of " - 'the\n' - ' operands.\n' - '\n' - '[4] Cased characters are those with general category ' - 'property\n' - ' being one of "Lu" (Letter, uppercase), "Ll" (Letter, ' - 'lowercase),\n' - ' or "Lt" (Letter, titlecase).\n' - '\n' - '[5] To format only a tuple you should therefore provide a\n' - ' singleton tuple whose only element is the tuple to be ' - 'formatted.\n' - '\n' - '[6] The advantage of leaving the newline on is that ' - 'returning an\n' - ' empty string is then an unambiguous EOF indication. It ' - 'is also\n' - ' possible (in cases where it might matter, for example, ' - 'if you want\n' - ' to make an exact copy of a file while scanning its ' - 'lines) to tell\n' - ' whether the last line of a file ended in a newline or ' - 'not (yes\n' - ' this happens!).\n', - 'specialnames': '\n' - 'Special method names\n' - '********************\n' - '\n' - 'A class can implement certain operations that are invoked by ' - 'special\n' - 'syntax (such as arithmetic operations or subscripting and ' - 'slicing) by\n' - "defining methods with special names. This is Python's " - 'approach to\n' - '*operator overloading*, allowing classes to define their own ' - 'behavior\n' - 'with respect to language operators. For instance, if a ' - 'class defines\n' - 'a method named "__getitem__()", and "x" is an instance of ' - 'this class,\n' - 'then "x[i]" is roughly equivalent to "x.__getitem__(i)" for ' - 'old-style\n' - 'classes and "type(x).__getitem__(x, i)" for new-style ' - 'classes. Except\n' - 'where mentioned, attempts to execute an operation raise an ' - 'exception\n' - 'when no appropriate method is defined (typically ' - '"AttributeError" or\n' - '"TypeError").\n' - '\n' - 'When implementing a class that emulates any built-in type, ' - 'it is\n' - 'important that the emulation only be implemented to the ' - 'degree that it\n' - 'makes sense for the object being modelled. For example, ' - 'some\n' - 'sequences may work well with retrieval of individual ' - 'elements, but\n' - 'extracting a slice may not make sense. (One example of this ' - 'is the\n' - '"NodeList" interface in the W3C\'s Document Object Model.)\n' - '\n' - '\n' - 'Basic customization\n' - '===================\n' - '\n' - 'object.__new__(cls[, ...])\n' - '\n' - ' Called to create a new instance of class *cls*. ' - '"__new__()" is a\n' - ' static method (special-cased so you need not declare it ' - 'as such)\n' - ' that takes the class of which an instance was requested ' - 'as its\n' - ' first argument. The remaining arguments are those passed ' - 'to the\n' - ' object constructor expression (the call to the class). ' - 'The return\n' - ' value of "__new__()" should be the new object instance ' - '(usually an\n' - ' instance of *cls*).\n' - '\n' - ' Typical implementations create a new instance of the ' - 'class by\n' - ' invoking the superclass\'s "__new__()" method using\n' - ' "super(currentclass, cls).__new__(cls[, ...])" with ' - 'appropriate\n' - ' arguments and then modifying the newly-created instance ' - 'as\n' - ' necessary before returning it.\n' - '\n' - ' If "__new__()" returns an instance of *cls*, then the ' - 'new\n' - ' instance\'s "__init__()" method will be invoked like\n' - ' "__init__(self[, ...])", where *self* is the new instance ' - 'and the\n' - ' remaining arguments are the same as were passed to ' - '"__new__()".\n' - '\n' - ' If "__new__()" does not return an instance of *cls*, then ' - 'the new\n' - ' instance\'s "__init__()" method will not be invoked.\n' - '\n' - ' "__new__()" is intended mainly to allow subclasses of ' - 'immutable\n' - ' types (like int, str, or tuple) to customize instance ' - 'creation. It\n' - ' is also commonly overridden in custom metaclasses in ' - 'order to\n' - ' customize class creation.\n' - '\n' - 'object.__init__(self[, ...])\n' - '\n' - ' Called after the instance has been created (by ' - '"__new__()"), but\n' - ' before it is returned to the caller. The arguments are ' - 'those\n' - ' passed to the class constructor expression. If a base ' - 'class has an\n' - ' "__init__()" method, the derived class\'s "__init__()" ' - 'method, if\n' - ' any, must explicitly call it to ensure proper ' - 'initialization of the\n' - ' base class part of the instance; for example:\n' - ' "BaseClass.__init__(self, [args...])".\n' - '\n' - ' Because "__new__()" and "__init__()" work together in ' - 'constructing\n' - ' objects ("__new__()" to create it, and "__init__()" to ' - 'customise\n' - ' it), no non-"None" value may be returned by "__init__()"; ' - 'doing so\n' - ' will cause a "TypeError" to be raised at runtime.\n' - '\n' - 'object.__del__(self)\n' - '\n' - ' Called when the instance is about to be destroyed. This ' - 'is also\n' - ' called a destructor. If a base class has a "__del__()" ' - 'method, the\n' - ' derived class\'s "__del__()" method, if any, must ' - 'explicitly call it\n' - ' to ensure proper deletion of the base class part of the ' - 'instance.\n' - ' Note that it is possible (though not recommended!) for ' - 'the\n' - ' "__del__()" method to postpone destruction of the ' - 'instance by\n' - ' creating a new reference to it. It may then be called at ' - 'a later\n' - ' time when this new reference is deleted. It is not ' - 'guaranteed that\n' - ' "__del__()" methods are called for objects that still ' - 'exist when\n' - ' the interpreter exits.\n' - '\n' - ' Note: "del x" doesn\'t directly call "x.__del__()" --- ' - 'the former\n' - ' decrements the reference count for "x" by one, and the ' - 'latter is\n' - ' only called when "x"\'s reference count reaches zero. ' - 'Some common\n' - ' situations that may prevent the reference count of an ' - 'object from\n' - ' going to zero include: circular references between ' - 'objects (e.g.,\n' - ' a doubly-linked list or a tree data structure with ' - 'parent and\n' - ' child pointers); a reference to the object on the stack ' - 'frame of\n' - ' a function that caught an exception (the traceback ' - 'stored in\n' - ' "sys.exc_traceback" keeps the stack frame alive); or a ' - 'reference\n' - ' to the object on the stack frame that raised an ' - 'unhandled\n' - ' exception in interactive mode (the traceback stored in\n' - ' "sys.last_traceback" keeps the stack frame alive). The ' - 'first\n' - ' situation can only be remedied by explicitly breaking ' - 'the cycles;\n' - ' the latter two situations can be resolved by storing ' - '"None" in\n' - ' "sys.exc_traceback" or "sys.last_traceback". Circular ' - 'references\n' - ' which are garbage are detected when the option cycle ' - 'detector is\n' - " enabled (it's on by default), but can only be cleaned " - 'up if there\n' - ' are no Python-level "__del__()" methods involved. Refer ' - 'to the\n' - ' documentation for the "gc" module for more information ' - 'about how\n' - ' "__del__()" methods are handled by the cycle detector,\n' - ' particularly the description of the "garbage" value.\n' - '\n' - ' Warning: Due to the precarious circumstances under which\n' - ' "__del__()" methods are invoked, exceptions that occur ' - 'during\n' - ' their execution are ignored, and a warning is printed ' - 'to\n' - ' "sys.stderr" instead. Also, when "__del__()" is invoked ' - 'in\n' - ' response to a module being deleted (e.g., when ' - 'execution of the\n' - ' program is done), other globals referenced by the ' - '"__del__()"\n' - ' method may already have been deleted or in the process ' - 'of being\n' - ' torn down (e.g. the import machinery shutting down). ' - 'For this\n' - ' reason, "__del__()" methods should do the absolute ' - 'minimum needed\n' - ' to maintain external invariants. Starting with version ' - '1.5,\n' - ' Python guarantees that globals whose name begins with a ' - 'single\n' - ' underscore are deleted from their module before other ' - 'globals are\n' - ' deleted; if no other references to such globals exist, ' - 'this may\n' - ' help in assuring that imported modules are still ' - 'available at the\n' - ' time when the "__del__()" method is called.\n' - '\n' - ' See also the "-R" command-line option.\n' - '\n' - 'object.__repr__(self)\n' - '\n' - ' Called by the "repr()" built-in function and by string ' - 'conversions\n' - ' (reverse quotes) to compute the "official" string ' - 'representation of\n' - ' an object. If at all possible, this should look like a ' - 'valid\n' - ' Python expression that could be used to recreate an ' - 'object with the\n' - ' same value (given an appropriate environment). If this ' - 'is not\n' - ' possible, a string of the form "<...some useful ' - 'description...>"\n' - ' should be returned. The return value must be a string ' - 'object. If a\n' - ' class defines "__repr__()" but not "__str__()", then ' - '"__repr__()"\n' - ' is also used when an "informal" string representation of ' - 'instances\n' - ' of that class is required.\n' - '\n' - ' This is typically used for debugging, so it is important ' - 'that the\n' - ' representation is information-rich and unambiguous.\n' - '\n' - 'object.__str__(self)\n' - '\n' - ' Called by the "str()" built-in function and by the ' - '"print"\n' - ' statement to compute the "informal" string representation ' - 'of an\n' - ' object. This differs from "__repr__()" in that it does ' - 'not have to\n' - ' be a valid Python expression: a more convenient or ' - 'concise\n' - ' representation may be used instead. The return value must ' - 'be a\n' - ' string object.\n' - '\n' - 'object.__lt__(self, other)\n' - 'object.__le__(self, other)\n' - 'object.__eq__(self, other)\n' - 'object.__ne__(self, other)\n' - 'object.__gt__(self, other)\n' - 'object.__ge__(self, other)\n' - '\n' - ' New in version 2.1.\n' - '\n' - ' These are the so-called "rich comparison" methods, and ' - 'are called\n' - ' for comparison operators in preference to "__cmp__()" ' - 'below. The\n' - ' correspondence between operator symbols and method names ' - 'is as\n' - ' follows: "x<y" calls "x.__lt__(y)", "x<=y" calls ' - '"x.__le__(y)",\n' - ' "x==y" calls "x.__eq__(y)", "x!=y" and "x<>y" call ' - '"x.__ne__(y)",\n' - ' "x>y" calls "x.__gt__(y)", and "x>=y" calls ' - '"x.__ge__(y)".\n' - '\n' - ' A rich comparison method may return the singleton ' - '"NotImplemented"\n' - ' if it does not implement the operation for a given pair ' - 'of\n' - ' arguments. By convention, "False" and "True" are returned ' - 'for a\n' - ' successful comparison. However, these methods can return ' - 'any value,\n' - ' so if the comparison operator is used in a Boolean ' - 'context (e.g.,\n' - ' in the condition of an "if" statement), Python will call ' - '"bool()"\n' - ' on the value to determine if the result is true or ' - 'false.\n' - '\n' - ' There are no implied relationships among the comparison ' - 'operators.\n' - ' The truth of "x==y" does not imply that "x!=y" is false.\n' - ' Accordingly, when defining "__eq__()", one should also ' - 'define\n' - ' "__ne__()" so that the operators will behave as ' - 'expected. See the\n' - ' paragraph on "__hash__()" for some important notes on ' - 'creating\n' - ' *hashable* objects which support custom comparison ' - 'operations and\n' - ' are usable as dictionary keys.\n' - '\n' - ' There are no swapped-argument versions of these methods ' - '(to be used\n' - ' when the left argument does not support the operation but ' - 'the right\n' - ' argument does); rather, "__lt__()" and "__gt__()" are ' - "each other's\n" - ' reflection, "__le__()" and "__ge__()" are each other\'s ' - 'reflection,\n' - ' and "__eq__()" and "__ne__()" are their own reflection.\n' - '\n' - ' Arguments to rich comparison methods are never coerced.\n' - '\n' - ' To automatically generate ordering operations from a ' - 'single root\n' - ' operation, see "functools.total_ordering()".\n' - '\n' - 'object.__cmp__(self, other)\n' - '\n' - ' Called by comparison operations if rich comparison (see ' - 'above) is\n' - ' not defined. Should return a negative integer if "self < ' - 'other",\n' - ' zero if "self == other", a positive integer if "self > ' - 'other". If\n' - ' no "__cmp__()", "__eq__()" or "__ne__()" operation is ' - 'defined,\n' - ' class instances are compared by object identity ' - '("address"). See\n' - ' also the description of "__hash__()" for some important ' - 'notes on\n' - ' creating *hashable* objects which support custom ' - 'comparison\n' - ' operations and are usable as dictionary keys. (Note: the\n' - ' restriction that exceptions are not propagated by ' - '"__cmp__()" has\n' - ' been removed since Python 1.5.)\n' - '\n' - 'object.__rcmp__(self, other)\n' - '\n' - ' Changed in version 2.1: No longer supported.\n' - '\n' - 'object.__hash__(self)\n' - '\n' - ' Called by built-in function "hash()" and for operations ' - 'on members\n' - ' of hashed collections including "set", "frozenset", and ' - '"dict".\n' - ' "__hash__()" should return an integer. The only required ' - 'property\n' - ' is that objects which compare equal have the same hash ' - 'value; it is\n' - ' advised to mix together the hash values of the components ' - 'of the\n' - ' object that also play a part in comparison of objects by ' - 'packing\n' - ' them into a tuple and hashing the tuple. Example:\n' - '\n' - ' def __hash__(self):\n' - ' return hash((self.name, self.nick, self.color))\n' - '\n' - ' If a class does not define a "__cmp__()" or "__eq__()" ' - 'method it\n' - ' should not define a "__hash__()" operation either; if it ' - 'defines\n' - ' "__cmp__()" or "__eq__()" but not "__hash__()", its ' - 'instances will\n' - ' not be usable in hashed collections. If a class defines ' - 'mutable\n' - ' objects and implements a "__cmp__()" or "__eq__()" ' - 'method, it\n' - ' should not implement "__hash__()", since hashable ' - 'collection\n' - " implementations require that an object's hash value is " - 'immutable\n' - " (if the object's hash value changes, it will be in the " - 'wrong hash\n' - ' bucket).\n' - '\n' - ' User-defined classes have "__cmp__()" and "__hash__()" ' - 'methods by\n' - ' default; with them, all objects compare unequal (except ' - 'with\n' - ' themselves) and "x.__hash__()" returns a result derived ' - 'from\n' - ' "id(x)".\n' - '\n' - ' Classes which inherit a "__hash__()" method from a parent ' - 'class but\n' - ' change the meaning of "__cmp__()" or "__eq__()" such that ' - 'the hash\n' - ' value returned is no longer appropriate (e.g. by ' - 'switching to a\n' - ' value-based concept of equality instead of the default ' - 'identity\n' - ' based equality) can explicitly flag themselves as being ' - 'unhashable\n' - ' by setting "__hash__ = None" in the class definition. ' - 'Doing so\n' - ' means that not only will instances of the class raise an\n' - ' appropriate "TypeError" when a program attempts to ' - 'retrieve their\n' - ' hash value, but they will also be correctly identified ' - 'as\n' - ' unhashable when checking "isinstance(obj, ' - 'collections.Hashable)"\n' - ' (unlike classes which define their own "__hash__()" to ' - 'explicitly\n' - ' raise "TypeError").\n' - '\n' - ' Changed in version 2.5: "__hash__()" may now also return ' - 'a long\n' - ' integer object; the 32-bit integer is then derived from ' - 'the hash of\n' - ' that object.\n' - '\n' - ' Changed in version 2.6: "__hash__" may now be set to ' - '"None" to\n' - ' explicitly flag instances of a class as unhashable.\n' - '\n' - 'object.__nonzero__(self)\n' - '\n' - ' Called to implement truth value testing and the built-in ' - 'operation\n' - ' "bool()"; should return "False" or "True", or their ' - 'integer\n' - ' equivalents "0" or "1". When this method is not ' - 'defined,\n' - ' "__len__()" is called, if it is defined, and the object ' - 'is\n' - ' considered true if its result is nonzero. If a class ' - 'defines\n' - ' neither "__len__()" nor "__nonzero__()", all its ' - 'instances are\n' - ' considered true.\n' - '\n' - 'object.__unicode__(self)\n' - '\n' - ' Called to implement "unicode()" built-in; should return a ' - 'Unicode\n' - ' object. When this method is not defined, string ' - 'conversion is\n' - ' attempted, and the result of string conversion is ' - 'converted to\n' - ' Unicode using the system default encoding.\n' - '\n' - '\n' - 'Customizing attribute access\n' - '============================\n' - '\n' - 'The following methods can be defined to customize the ' - 'meaning of\n' - 'attribute access (use of, assignment to, or deletion of ' - '"x.name") for\n' - 'class instances.\n' - '\n' - 'object.__getattr__(self, name)\n' - '\n' - ' Called when an attribute lookup has not found the ' - 'attribute in the\n' - ' usual places (i.e. it is not an instance attribute nor is ' - 'it found\n' - ' in the class tree for "self"). "name" is the attribute ' - 'name. This\n' - ' method should return the (computed) attribute value or ' - 'raise an\n' - ' "AttributeError" exception.\n' - '\n' - ' Note that if the attribute is found through the normal ' - 'mechanism,\n' - ' "__getattr__()" is not called. (This is an intentional ' - 'asymmetry\n' - ' between "__getattr__()" and "__setattr__()".) This is ' - 'done both for\n' - ' efficiency reasons and because otherwise "__getattr__()" ' - 'would have\n' - ' no way to access other attributes of the instance. Note ' - 'that at\n' - ' least for instance variables, you can fake total control ' - 'by not\n' - ' inserting any values in the instance attribute dictionary ' - '(but\n' - ' instead inserting them in another object). See the\n' - ' "__getattribute__()" method below for a way to actually ' - 'get total\n' - ' control in new-style classes.\n' - '\n' - 'object.__setattr__(self, name, value)\n' - '\n' - ' Called when an attribute assignment is attempted. This ' - 'is called\n' - ' instead of the normal mechanism (i.e. store the value in ' - 'the\n' - ' instance dictionary). *name* is the attribute name, ' - '*value* is the\n' - ' value to be assigned to it.\n' - '\n' - ' If "__setattr__()" wants to assign to an instance ' - 'attribute, it\n' - ' should not simply execute "self.name = value" --- this ' - 'would cause\n' - ' a recursive call to itself. Instead, it should insert ' - 'the value in\n' - ' the dictionary of instance attributes, e.g., ' - '"self.__dict__[name] =\n' - ' value". For new-style classes, rather than accessing the ' - 'instance\n' - ' dictionary, it should call the base class method with the ' - 'same\n' - ' name, for example, "object.__setattr__(self, name, ' - 'value)".\n' - '\n' - 'object.__delattr__(self, name)\n' - '\n' - ' Like "__setattr__()" but for attribute deletion instead ' - 'of\n' - ' assignment. This should only be implemented if "del ' - 'obj.name" is\n' - ' meaningful for the object.\n' - '\n' - '\n' - 'More attribute access for new-style classes\n' - '-------------------------------------------\n' - '\n' - 'The following methods only apply to new-style classes.\n' - '\n' - 'object.__getattribute__(self, name)\n' - '\n' - ' Called unconditionally to implement attribute accesses ' - 'for\n' - ' instances of the class. If the class also defines ' - '"__getattr__()",\n' - ' the latter will not be called unless "__getattribute__()" ' - 'either\n' - ' calls it explicitly or raises an "AttributeError". This ' - 'method\n' - ' should return the (computed) attribute value or raise an\n' - ' "AttributeError" exception. In order to avoid infinite ' - 'recursion in\n' - ' this method, its implementation should always call the ' - 'base class\n' - ' method with the same name to access any attributes it ' - 'needs, for\n' - ' example, "object.__getattribute__(self, name)".\n' - '\n' - ' Note: This method may still be bypassed when looking up ' - 'special\n' - ' methods as the result of implicit invocation via ' - 'language syntax\n' - ' or built-in functions. See Special method lookup for ' - 'new-style\n' - ' classes.\n' - '\n' - '\n' - 'Implementing Descriptors\n' - '------------------------\n' - '\n' - 'The following methods only apply when an instance of the ' - 'class\n' - 'containing the method (a so-called *descriptor* class) ' - 'appears in an\n' - "*owner* class (the descriptor must be in either the owner's " - 'class\n' - 'dictionary or in the class dictionary for one of its ' - 'parents). In the\n' - 'examples below, "the attribute" refers to the attribute ' - 'whose name is\n' - 'the key of the property in the owner class\' "__dict__".\n' - '\n' - 'object.__get__(self, instance, owner)\n' - '\n' - ' Called to get the attribute of the owner class (class ' - 'attribute\n' - ' access) or of an instance of that class (instance ' - 'attribute\n' - ' access). *owner* is always the owner class, while ' - '*instance* is the\n' - ' instance that the attribute was accessed through, or ' - '"None" when\n' - ' the attribute is accessed through the *owner*. This ' - 'method should\n' - ' return the (computed) attribute value or raise an ' - '"AttributeError"\n' - ' exception.\n' - '\n' - 'object.__set__(self, instance, value)\n' - '\n' - ' Called to set the attribute on an instance *instance* of ' - 'the owner\n' - ' class to a new value, *value*.\n' - '\n' - 'object.__delete__(self, instance)\n' - '\n' - ' Called to delete the attribute on an instance *instance* ' - 'of the\n' - ' owner class.\n' - '\n' - '\n' - 'Invoking Descriptors\n' - '--------------------\n' - '\n' - 'In general, a descriptor is an object attribute with ' - '"binding\n' - 'behavior", one whose attribute access has been overridden by ' - 'methods\n' - 'in the descriptor protocol: "__get__()", "__set__()", and\n' - '"__delete__()". If any of those methods are defined for an ' - 'object, it\n' - 'is said to be a descriptor.\n' - '\n' - 'The default behavior for attribute access is to get, set, or ' - 'delete\n' - "the attribute from an object's dictionary. For instance, " - '"a.x" has a\n' - 'lookup chain starting with "a.__dict__[\'x\']", then\n' - '"type(a).__dict__[\'x\']", and continuing through the base ' - 'classes of\n' - '"type(a)" excluding metaclasses.\n' - '\n' - 'However, if the looked-up value is an object defining one of ' - 'the\n' - 'descriptor methods, then Python may override the default ' - 'behavior and\n' - 'invoke the descriptor method instead. Where this occurs in ' - 'the\n' - 'precedence chain depends on which descriptor methods were ' - 'defined and\n' - 'how they were called. Note that descriptors are only ' - 'invoked for new\n' - 'style objects or classes (ones that subclass "object()" or ' - '"type()").\n' - '\n' - 'The starting point for descriptor invocation is a binding, ' - '"a.x". How\n' - 'the arguments are assembled depends on "a":\n' - '\n' - 'Direct Call\n' - ' The simplest and least common call is when user code ' - 'directly\n' - ' invokes a descriptor method: "x.__get__(a)".\n' - '\n' - 'Instance Binding\n' - ' If binding to a new-style object instance, "a.x" is ' - 'transformed\n' - ' into the call: "type(a).__dict__[\'x\'].__get__(a, ' - 'type(a))".\n' - '\n' - 'Class Binding\n' - ' If binding to a new-style class, "A.x" is transformed ' - 'into the\n' - ' call: "A.__dict__[\'x\'].__get__(None, A)".\n' - '\n' - 'Super Binding\n' - ' If "a" is an instance of "super", then the binding ' - '"super(B,\n' - ' obj).m()" searches "obj.__class__.__mro__" for the base ' - 'class "A"\n' - ' immediately preceding "B" and then invokes the descriptor ' - 'with the\n' - ' call: "A.__dict__[\'m\'].__get__(obj, obj.__class__)".\n' - '\n' - 'For instance bindings, the precedence of descriptor ' - 'invocation depends\n' - 'on the which descriptor methods are defined. A descriptor ' - 'can define\n' - 'any combination of "__get__()", "__set__()" and ' - '"__delete__()". If it\n' - 'does not define "__get__()", then accessing the attribute ' - 'will return\n' - 'the descriptor object itself unless there is a value in the ' - "object's\n" - 'instance dictionary. If the descriptor defines "__set__()" ' - 'and/or\n' - '"__delete__()", it is a data descriptor; if it defines ' - 'neither, it is\n' - 'a non-data descriptor. Normally, data descriptors define ' - 'both\n' - '"__get__()" and "__set__()", while non-data descriptors have ' - 'just the\n' - '"__get__()" method. Data descriptors with "__set__()" and ' - '"__get__()"\n' - 'defined always override a redefinition in an instance ' - 'dictionary. In\n' - 'contrast, non-data descriptors can be overridden by ' - 'instances.\n' - '\n' - 'Python methods (including "staticmethod()" and ' - '"classmethod()") are\n' - 'implemented as non-data descriptors. Accordingly, instances ' - 'can\n' - 'redefine and override methods. This allows individual ' - 'instances to\n' - 'acquire behaviors that differ from other instances of the ' - 'same class.\n' - '\n' - 'The "property()" function is implemented as a data ' - 'descriptor.\n' - 'Accordingly, instances cannot override the behavior of a ' - 'property.\n' - '\n' - '\n' - '__slots__\n' - '---------\n' - '\n' - 'By default, instances of both old and new-style classes have ' - 'a\n' - 'dictionary for attribute storage. This wastes space for ' - 'objects\n' - 'having very few instance variables. The space consumption ' - 'can become\n' - 'acute when creating large numbers of instances.\n' - '\n' - 'The default can be overridden by defining *__slots__* in a ' - 'new-style\n' - 'class definition. The *__slots__* declaration takes a ' - 'sequence of\n' - 'instance variables and reserves just enough space in each ' - 'instance to\n' - 'hold a value for each variable. Space is saved because ' - '*__dict__* is\n' - 'not created for each instance.\n' - '\n' - '__slots__\n' - '\n' - ' This class variable can be assigned a string, iterable, ' - 'or sequence\n' - ' of strings with variable names used by instances. If ' - 'defined in a\n' - ' new-style class, *__slots__* reserves space for the ' - 'declared\n' - ' variables and prevents the automatic creation of ' - '*__dict__* and\n' - ' *__weakref__* for each instance.\n' - '\n' - ' New in version 2.2.\n' - '\n' - 'Notes on using *__slots__*\n' - '\n' - '* When inheriting from a class without *__slots__*, the ' - '*__dict__*\n' - ' attribute of that class will always be accessible, so a ' - '*__slots__*\n' - ' definition in the subclass is meaningless.\n' - '\n' - '* Without a *__dict__* variable, instances cannot be ' - 'assigned new\n' - ' variables not listed in the *__slots__* definition. ' - 'Attempts to\n' - ' assign to an unlisted variable name raises ' - '"AttributeError". If\n' - ' dynamic assignment of new variables is desired, then add\n' - ' "\'__dict__\'" to the sequence of strings in the ' - '*__slots__*\n' - ' declaration.\n' - '\n' - ' Changed in version 2.3: Previously, adding "\'__dict__\'" ' - 'to the\n' - ' *__slots__* declaration would not enable the assignment of ' - 'new\n' - ' attributes not specifically listed in the sequence of ' - 'instance\n' - ' variable names.\n' - '\n' - '* Without a *__weakref__* variable for each instance, ' - 'classes\n' - ' defining *__slots__* do not support weak references to ' - 'its\n' - ' instances. If weak reference support is needed, then add\n' - ' "\'__weakref__\'" to the sequence of strings in the ' - '*__slots__*\n' - ' declaration.\n' - '\n' - ' Changed in version 2.3: Previously, adding ' - '"\'__weakref__\'" to the\n' - ' *__slots__* declaration would not enable support for weak\n' - ' references.\n' - '\n' - '* *__slots__* are implemented at the class level by ' - 'creating\n' - ' descriptors (Implementing Descriptors) for each variable ' - 'name. As a\n' - ' result, class attributes cannot be used to set default ' - 'values for\n' - ' instance variables defined by *__slots__*; otherwise, the ' - 'class\n' - ' attribute would overwrite the descriptor assignment.\n' - '\n' - '* The action of a *__slots__* declaration is limited to the ' - 'class\n' - ' where it is defined. As a result, subclasses will have a ' - '*__dict__*\n' - ' unless they also define *__slots__* (which must only ' - 'contain names\n' - ' of any *additional* slots).\n' - '\n' - '* If a class defines a slot also defined in a base class, ' - 'the\n' - ' instance variable defined by the base class slot is ' - 'inaccessible\n' - ' (except by retrieving its descriptor directly from the ' - 'base class).\n' - ' This renders the meaning of the program undefined. In the ' - 'future, a\n' - ' check may be added to prevent this.\n' - '\n' - '* Nonempty *__slots__* does not work for classes derived ' - 'from\n' - ' "variable-length" built-in types such as "long", "str" and ' - '"tuple".\n' - '\n' - '* Any non-string iterable may be assigned to *__slots__*. ' - 'Mappings\n' - ' may also be used; however, in the future, special meaning ' - 'may be\n' - ' assigned to the values corresponding to each key.\n' - '\n' - '* *__class__* assignment works only if both classes have the ' - 'same\n' - ' *__slots__*.\n' - '\n' - ' Changed in version 2.6: Previously, *__class__* assignment ' - 'raised an\n' - ' error if either new or old class had *__slots__*.\n' - '\n' - '\n' - 'Customizing class creation\n' - '==========================\n' - '\n' - 'By default, new-style classes are constructed using ' - '"type()". A class\n' - 'definition is read into a separate namespace and the value ' - 'of class\n' - 'name is bound to the result of "type(name, bases, dict)".\n' - '\n' - 'When the class definition is read, if *__metaclass__* is ' - 'defined then\n' - 'the callable assigned to it will be called instead of ' - '"type()". This\n' - 'allows classes or functions to be written which monitor or ' - 'alter the\n' - 'class creation process:\n' - '\n' - '* Modifying the class dictionary prior to the class being ' - 'created.\n' - '\n' - '* Returning an instance of another class -- essentially ' - 'performing\n' - ' the role of a factory function.\n' - '\n' - "These steps will have to be performed in the metaclass's " - '"__new__()"\n' - 'method -- "type.__new__()" can then be called from this ' - 'method to\n' - 'create a class with different properties. This example adds ' - 'a new\n' - 'element to the class dictionary before creating the class:\n' - '\n' - ' class metacls(type):\n' - ' def __new__(mcs, name, bases, dict):\n' - " dict['foo'] = 'metacls was here'\n" - ' return type.__new__(mcs, name, bases, dict)\n' - '\n' - 'You can of course also override other class methods (or add ' - 'new\n' - 'methods); for example defining a custom "__call__()" method ' - 'in the\n' - 'metaclass allows custom behavior when the class is called, ' - 'e.g. not\n' - 'always creating a new instance.\n' - '\n' - '__metaclass__\n' - '\n' - ' This variable can be any callable accepting arguments for ' - '"name",\n' - ' "bases", and "dict". Upon class creation, the callable ' - 'is used\n' - ' instead of the built-in "type()".\n' - '\n' - ' New in version 2.2.\n' - '\n' - 'The appropriate metaclass is determined by the following ' - 'precedence\n' - 'rules:\n' - '\n' - '* If "dict[\'__metaclass__\']" exists, it is used.\n' - '\n' - '* Otherwise, if there is at least one base class, its ' - 'metaclass is\n' - ' used (this looks for a *__class__* attribute first and if ' - 'not found,\n' - ' uses its type).\n' - '\n' - '* Otherwise, if a global variable named __metaclass__ ' - 'exists, it is\n' - ' used.\n' - '\n' - '* Otherwise, the old-style, classic metaclass ' - '(types.ClassType) is\n' - ' used.\n' - '\n' - 'The potential uses for metaclasses are boundless. Some ideas ' - 'that have\n' - 'been explored including logging, interface checking, ' - 'automatic\n' - 'delegation, automatic property creation, proxies, ' - 'frameworks, and\n' - 'automatic resource locking/synchronization.\n' - '\n' - '\n' - 'Customizing instance and subclass checks\n' - '========================================\n' - '\n' - 'New in version 2.6.\n' - '\n' - 'The following methods are used to override the default ' - 'behavior of the\n' - '"isinstance()" and "issubclass()" built-in functions.\n' - '\n' - 'In particular, the metaclass "abc.ABCMeta" implements these ' - 'methods in\n' - 'order to allow the addition of Abstract Base Classes (ABCs) ' - 'as\n' - '"virtual base classes" to any class or type (including ' - 'built-in\n' - 'types), including other ABCs.\n' - '\n' - 'class.__instancecheck__(self, instance)\n' - '\n' - ' Return true if *instance* should be considered a (direct ' - 'or\n' - ' indirect) instance of *class*. If defined, called to ' - 'implement\n' - ' "isinstance(instance, class)".\n' - '\n' - 'class.__subclasscheck__(self, subclass)\n' - '\n' - ' Return true if *subclass* should be considered a (direct ' - 'or\n' - ' indirect) subclass of *class*. If defined, called to ' - 'implement\n' - ' "issubclass(subclass, class)".\n' - '\n' - 'Note that these methods are looked up on the type ' - '(metaclass) of a\n' - 'class. They cannot be defined as class methods in the ' - 'actual class.\n' - 'This is consistent with the lookup of special methods that ' - 'are called\n' - 'on instances, only in this case the instance is itself a ' - 'class.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 3119** - Introducing Abstract Base Classes\n' - ' Includes the specification for customizing ' - '"isinstance()" and\n' - ' "issubclass()" behavior through "__instancecheck__()" ' - 'and\n' - ' "__subclasscheck__()", with motivation for this ' - 'functionality in\n' - ' the context of adding Abstract Base Classes (see the ' - '"abc"\n' - ' module) to the language.\n' - '\n' - '\n' - 'Emulating callable objects\n' - '==========================\n' - '\n' - 'object.__call__(self[, args...])\n' - '\n' - ' Called when the instance is "called" as a function; if ' - 'this method\n' - ' is defined, "x(arg1, arg2, ...)" is a shorthand for\n' - ' "x.__call__(arg1, arg2, ...)".\n' - '\n' - '\n' - 'Emulating container types\n' - '=========================\n' - '\n' - 'The following methods can be defined to implement container ' - 'objects.\n' - 'Containers usually are sequences (such as lists or tuples) ' - 'or mappings\n' - '(like dictionaries), but can represent other containers as ' - 'well. The\n' - 'first set of methods is used either to emulate a sequence or ' - 'to\n' - 'emulate a mapping; the difference is that for a sequence, ' - 'the\n' - 'allowable keys should be the integers *k* for which "0 <= k ' - '< N" where\n' - '*N* is the length of the sequence, or slice objects, which ' - 'define a\n' - 'range of items. (For backwards compatibility, the method\n' - '"__getslice__()" (see below) can also be defined to handle ' - 'simple, but\n' - 'not extended slices.) It is also recommended that mappings ' - 'provide the\n' - 'methods "keys()", "values()", "items()", "has_key()", ' - '"get()",\n' - '"clear()", "setdefault()", "iterkeys()", "itervalues()",\n' - '"iteritems()", "pop()", "popitem()", "copy()", and ' - '"update()" behaving\n' - "similar to those for Python's standard dictionary objects. " - 'The\n' - '"UserDict" module provides a "DictMixin" class to help ' - 'create those\n' - 'methods from a base set of "__getitem__()", ' - '"__setitem__()",\n' - '"__delitem__()", and "keys()". Mutable sequences should ' - 'provide\n' - 'methods "append()", "count()", "index()", "extend()", ' - '"insert()",\n' - '"pop()", "remove()", "reverse()" and "sort()", like Python ' - 'standard\n' - 'list objects. Finally, sequence types should implement ' - 'addition\n' - '(meaning concatenation) and multiplication (meaning ' - 'repetition) by\n' - 'defining the methods "__add__()", "__radd__()", ' - '"__iadd__()",\n' - '"__mul__()", "__rmul__()" and "__imul__()" described below; ' - 'they\n' - 'should not define "__coerce__()" or other numerical ' - 'operators. It is\n' - 'recommended that both mappings and sequences implement the\n' - '"__contains__()" method to allow efficient use of the "in" ' - 'operator;\n' - 'for mappings, "in" should be equivalent of "has_key()"; for ' - 'sequences,\n' - 'it should search through the values. It is further ' - 'recommended that\n' - 'both mappings and sequences implement the "__iter__()" ' - 'method to allow\n' - 'efficient iteration through the container; for mappings, ' - '"__iter__()"\n' - 'should be the same as "iterkeys()"; for sequences, it should ' - 'iterate\n' - 'through the values.\n' - '\n' - 'object.__len__(self)\n' - '\n' - ' Called to implement the built-in function "len()". ' - 'Should return\n' - ' the length of the object, an integer ">=" 0. Also, an ' - 'object that\n' - ' doesn\'t define a "__nonzero__()" method and whose ' - '"__len__()"\n' - ' method returns zero is considered to be false in a ' - 'Boolean context.\n' - '\n' - ' **CPython implementation detail:** In CPython, the length ' - 'is\n' - ' required to be at most "sys.maxsize". If the length is ' - 'larger than\n' - ' "sys.maxsize" some features (such as "len()") may raise\n' - ' "OverflowError". To prevent raising "OverflowError" by ' - 'truth value\n' - ' testing, an object must define a "__nonzero__()" method.\n' - '\n' - 'object.__getitem__(self, key)\n' - '\n' - ' Called to implement evaluation of "self[key]". For ' - 'sequence types,\n' - ' the accepted keys should be integers and slice objects. ' - 'Note that\n' - ' the special interpretation of negative indexes (if the ' - 'class wishes\n' - ' to emulate a sequence type) is up to the "__getitem__()" ' - 'method. If\n' - ' *key* is of an inappropriate type, "TypeError" may be ' - 'raised; if of\n' - ' a value outside the set of indexes for the sequence ' - '(after any\n' - ' special interpretation of negative values), "IndexError" ' - 'should be\n' - ' raised. For mapping types, if *key* is missing (not in ' - 'the\n' - ' container), "KeyError" should be raised.\n' - '\n' - ' Note: "for" loops expect that an "IndexError" will be ' - 'raised for\n' - ' illegal indexes to allow proper detection of the end of ' - 'the\n' - ' sequence.\n' - '\n' - 'object.__missing__(self, key)\n' - '\n' - ' Called by "dict"."__getitem__()" to implement "self[key]" ' - 'for dict\n' - ' subclasses when key is not in the dictionary.\n' - '\n' - 'object.__setitem__(self, key, value)\n' - '\n' - ' Called to implement assignment to "self[key]". Same note ' - 'as for\n' - ' "__getitem__()". This should only be implemented for ' - 'mappings if\n' - ' the objects support changes to the values for keys, or if ' - 'new keys\n' - ' can be added, or for sequences if elements can be ' - 'replaced. The\n' - ' same exceptions should be raised for improper *key* ' - 'values as for\n' - ' the "__getitem__()" method.\n' - '\n' - 'object.__delitem__(self, key)\n' - '\n' - ' Called to implement deletion of "self[key]". Same note ' - 'as for\n' - ' "__getitem__()". This should only be implemented for ' - 'mappings if\n' - ' the objects support removal of keys, or for sequences if ' - 'elements\n' - ' can be removed from the sequence. The same exceptions ' - 'should be\n' - ' raised for improper *key* values as for the ' - '"__getitem__()" method.\n' - '\n' - 'object.__iter__(self)\n' - '\n' - ' This method is called when an iterator is required for a ' - 'container.\n' - ' This method should return a new iterator object that can ' - 'iterate\n' - ' over all the objects in the container. For mappings, it ' - 'should\n' - ' iterate over the keys of the container, and should also ' - 'be made\n' - ' available as the method "iterkeys()".\n' - '\n' - ' Iterator objects also need to implement this method; they ' - 'are\n' - ' required to return themselves. For more information on ' - 'iterator\n' - ' objects, see Iterator Types.\n' - '\n' - 'object.__reversed__(self)\n' - '\n' - ' Called (if present) by the "reversed()" built-in to ' - 'implement\n' - ' reverse iteration. It should return a new iterator ' - 'object that\n' - ' iterates over all the objects in the container in reverse ' - 'order.\n' - '\n' - ' If the "__reversed__()" method is not provided, the ' - '"reversed()"\n' - ' built-in will fall back to using the sequence protocol ' - '("__len__()"\n' - ' and "__getitem__()"). Objects that support the sequence ' - 'protocol\n' - ' should only provide "__reversed__()" if they can provide ' - 'an\n' - ' implementation that is more efficient than the one ' - 'provided by\n' - ' "reversed()".\n' - '\n' - ' New in version 2.6.\n' - '\n' - 'The membership test operators ("in" and "not in") are ' - 'normally\n' - 'implemented as an iteration through a sequence. However, ' - 'container\n' - 'objects can supply the following special method with a more ' - 'efficient\n' - 'implementation, which also does not require the object be a ' - 'sequence.\n' - '\n' - 'object.__contains__(self, item)\n' - '\n' - ' Called to implement membership test operators. Should ' - 'return true\n' - ' if *item* is in *self*, false otherwise. For mapping ' - 'objects, this\n' - ' should consider the keys of the mapping rather than the ' - 'values or\n' - ' the key-item pairs.\n' - '\n' - ' For objects that don\'t define "__contains__()", the ' - 'membership test\n' - ' first tries iteration via "__iter__()", then the old ' - 'sequence\n' - ' iteration protocol via "__getitem__()", see this section ' - 'in the\n' - ' language reference.\n' - '\n' - '\n' - 'Additional methods for emulation of sequence types\n' - '==================================================\n' - '\n' - 'The following optional methods can be defined to further ' - 'emulate\n' - 'sequence objects. Immutable sequences methods should at ' - 'most only\n' - 'define "__getslice__()"; mutable sequences might define all ' - 'three\n' - 'methods.\n' - '\n' - 'object.__getslice__(self, i, j)\n' - '\n' - ' Deprecated since version 2.0: Support slice objects as ' - 'parameters\n' - ' to the "__getitem__()" method. (However, built-in types ' - 'in CPython\n' - ' currently still implement "__getslice__()". Therefore, ' - 'you have to\n' - ' override it in derived classes when implementing ' - 'slicing.)\n' - '\n' - ' Called to implement evaluation of "self[i:j]". The ' - 'returned object\n' - ' should be of the same type as *self*. Note that missing ' - '*i* or *j*\n' - ' in the slice expression are replaced by zero or ' - '"sys.maxsize",\n' - ' respectively. If negative indexes are used in the slice, ' - 'the\n' - ' length of the sequence is added to that index. If the ' - 'instance does\n' - ' not implement the "__len__()" method, an "AttributeError" ' - 'is\n' - ' raised. No guarantee is made that indexes adjusted this ' - 'way are not\n' - ' still negative. Indexes which are greater than the ' - 'length of the\n' - ' sequence are not modified. If no "__getslice__()" is ' - 'found, a slice\n' - ' object is created instead, and passed to "__getitem__()" ' - 'instead.\n' - '\n' - 'object.__setslice__(self, i, j, sequence)\n' - '\n' - ' Called to implement assignment to "self[i:j]". Same notes ' - 'for *i*\n' - ' and *j* as for "__getslice__()".\n' - '\n' - ' This method is deprecated. If no "__setslice__()" is ' - 'found, or for\n' - ' extended slicing of the form "self[i:j:k]", a slice ' - 'object is\n' - ' created, and passed to "__setitem__()", instead of ' - '"__setslice__()"\n' - ' being called.\n' - '\n' - 'object.__delslice__(self, i, j)\n' - '\n' - ' Called to implement deletion of "self[i:j]". Same notes ' - 'for *i* and\n' - ' *j* as for "__getslice__()". This method is deprecated. ' - 'If no\n' - ' "__delslice__()" is found, or for extended slicing of the ' - 'form\n' - ' "self[i:j:k]", a slice object is created, and passed to\n' - ' "__delitem__()", instead of "__delslice__()" being ' - 'called.\n' - '\n' - 'Notice that these methods are only invoked when a single ' - 'slice with a\n' - 'single colon is used, and the slice method is available. ' - 'For slice\n' - 'operations involving extended slice notation, or in absence ' - 'of the\n' - 'slice methods, "__getitem__()", "__setitem__()" or ' - '"__delitem__()" is\n' - 'called with a slice object as argument.\n' - '\n' - 'The following example demonstrate how to make your program ' - 'or module\n' - 'compatible with earlier versions of Python (assuming that ' - 'methods\n' - '"__getitem__()", "__setitem__()" and "__delitem__()" support ' - 'slice\n' - 'objects as arguments):\n' - '\n' - ' class MyClass:\n' - ' ...\n' - ' def __getitem__(self, index):\n' - ' ...\n' - ' def __setitem__(self, index, value):\n' - ' ...\n' - ' def __delitem__(self, index):\n' - ' ...\n' - '\n' - ' if sys.version_info < (2, 0):\n' - " # They won't be defined if version is at least " - '2.0 final\n' - '\n' - ' def __getslice__(self, i, j):\n' - ' return self[max(0, i):max(0, j):]\n' - ' def __setslice__(self, i, j, seq):\n' - ' self[max(0, i):max(0, j):] = seq\n' - ' def __delslice__(self, i, j):\n' - ' del self[max(0, i):max(0, j):]\n' - ' ...\n' - '\n' - 'Note the calls to "max()"; these are necessary because of ' - 'the handling\n' - 'of negative indices before the "__*slice__()" methods are ' - 'called.\n' - 'When negative indexes are used, the "__*item__()" methods ' - 'receive them\n' - 'as provided, but the "__*slice__()" methods get a "cooked" ' - 'form of the\n' - 'index values. For each negative index value, the length of ' - 'the\n' - 'sequence is added to the index before calling the method ' - '(which may\n' - 'still result in a negative index); this is the customary ' - 'handling of\n' - 'negative indexes by the built-in sequence types, and the ' - '"__*item__()"\n' - 'methods are expected to do this as well. However, since ' - 'they should\n' - 'already be doing that, negative indexes cannot be passed in; ' - 'they must\n' - 'be constrained to the bounds of the sequence before being ' - 'passed to\n' - 'the "__*item__()" methods. Calling "max(0, i)" conveniently ' - 'returns\n' - 'the proper value.\n' - '\n' - '\n' - 'Emulating numeric types\n' - '=======================\n' - '\n' - 'The following methods can be defined to emulate numeric ' - 'objects.\n' - 'Methods corresponding to operations that are not supported ' - 'by the\n' - 'particular kind of number implemented (e.g., bitwise ' - 'operations for\n' - 'non-integral numbers) should be left undefined.\n' - '\n' - 'object.__add__(self, other)\n' - 'object.__sub__(self, other)\n' - 'object.__mul__(self, other)\n' - 'object.__floordiv__(self, other)\n' - 'object.__mod__(self, other)\n' - 'object.__divmod__(self, other)\n' - 'object.__pow__(self, other[, modulo])\n' - 'object.__lshift__(self, other)\n' - 'object.__rshift__(self, other)\n' - 'object.__and__(self, other)\n' - 'object.__xor__(self, other)\n' - 'object.__or__(self, other)\n' - '\n' - ' These methods are called to implement the binary ' - 'arithmetic\n' - ' operations ("+", "-", "*", "//", "%", "divmod()", ' - '"pow()", "**",\n' - ' "<<", ">>", "&", "^", "|"). For instance, to evaluate ' - 'the\n' - ' expression "x + y", where *x* is an instance of a class ' - 'that has an\n' - ' "__add__()" method, "x.__add__(y)" is called. The ' - '"__divmod__()"\n' - ' method should be the equivalent to using "__floordiv__()" ' - 'and\n' - ' "__mod__()"; it should not be related to "__truediv__()" ' - '(described\n' - ' below). Note that "__pow__()" should be defined to ' - 'accept an\n' - ' optional third argument if the ternary version of the ' - 'built-in\n' - ' "pow()" function is to be supported.\n' - '\n' - ' If one of those methods does not support the operation ' - 'with the\n' - ' supplied arguments, it should return "NotImplemented".\n' - '\n' - 'object.__div__(self, other)\n' - 'object.__truediv__(self, other)\n' - '\n' - ' The division operator ("/") is implemented by these ' - 'methods. The\n' - ' "__truediv__()" method is used when "__future__.division" ' - 'is in\n' - ' effect, otherwise "__div__()" is used. If only one of ' - 'these two\n' - ' methods is defined, the object will not support division ' - 'in the\n' - ' alternate context; "TypeError" will be raised instead.\n' - '\n' - 'object.__radd__(self, other)\n' - 'object.__rsub__(self, other)\n' - 'object.__rmul__(self, other)\n' - 'object.__rdiv__(self, other)\n' - 'object.__rtruediv__(self, other)\n' - 'object.__rfloordiv__(self, other)\n' - 'object.__rmod__(self, other)\n' - 'object.__rdivmod__(self, other)\n' - 'object.__rpow__(self, other)\n' - 'object.__rlshift__(self, other)\n' - 'object.__rrshift__(self, other)\n' - 'object.__rand__(self, other)\n' - 'object.__rxor__(self, other)\n' - 'object.__ror__(self, other)\n' - '\n' - ' These methods are called to implement the binary ' - 'arithmetic\n' - ' operations ("+", "-", "*", "/", "%", "divmod()", "pow()", ' - '"**",\n' - ' "<<", ">>", "&", "^", "|") with reflected (swapped) ' - 'operands.\n' - ' These functions are only called if the left operand does ' - 'not\n' - ' support the corresponding operation and the operands are ' - 'of\n' - ' different types. [2] For instance, to evaluate the ' - 'expression "x -\n' - ' y", where *y* is an instance of a class that has an ' - '"__rsub__()"\n' - ' method, "y.__rsub__(x)" is called if "x.__sub__(y)" ' - 'returns\n' - ' *NotImplemented*.\n' - '\n' - ' Note that ternary "pow()" will not try calling ' - '"__rpow__()" (the\n' - ' coercion rules would become too complicated).\n' - '\n' - " Note: If the right operand's type is a subclass of the " - 'left\n' - " operand's type and that subclass provides the reflected " - 'method\n' - ' for the operation, this method will be called before ' - 'the left\n' - " operand's non-reflected method. This behavior allows " - 'subclasses\n' - " to override their ancestors' operations.\n" - '\n' - 'object.__iadd__(self, other)\n' - 'object.__isub__(self, other)\n' - 'object.__imul__(self, other)\n' - 'object.__idiv__(self, other)\n' - 'object.__itruediv__(self, other)\n' - 'object.__ifloordiv__(self, other)\n' - 'object.__imod__(self, other)\n' - 'object.__ipow__(self, other[, modulo])\n' - 'object.__ilshift__(self, other)\n' - 'object.__irshift__(self, other)\n' - 'object.__iand__(self, other)\n' - 'object.__ixor__(self, other)\n' - 'object.__ior__(self, other)\n' - '\n' - ' These methods are called to implement the augmented ' - 'arithmetic\n' - ' assignments ("+=", "-=", "*=", "/=", "//=", "%=", "**=", ' - '"<<=",\n' - ' ">>=", "&=", "^=", "|="). These methods should attempt ' - 'to do the\n' - ' operation in-place (modifying *self*) and return the ' - 'result (which\n' - ' could be, but does not have to be, *self*). If a ' - 'specific method\n' - ' is not defined, the augmented assignment falls back to ' - 'the normal\n' - ' methods. For instance, to execute the statement "x += ' - 'y", where\n' - ' *x* is an instance of a class that has an "__iadd__()" ' - 'method,\n' - ' "x.__iadd__(y)" is called. If *x* is an instance of a ' - 'class that\n' - ' does not define a "__iadd__()" method, "x.__add__(y)" ' - 'and\n' - ' "y.__radd__(x)" are considered, as with the evaluation of ' - '"x + y".\n' - '\n' - 'object.__neg__(self)\n' - 'object.__pos__(self)\n' - 'object.__abs__(self)\n' - 'object.__invert__(self)\n' - '\n' - ' Called to implement the unary arithmetic operations ("-", ' - '"+",\n' - ' "abs()" and "~").\n' - '\n' - 'object.__complex__(self)\n' - 'object.__int__(self)\n' - 'object.__long__(self)\n' - 'object.__float__(self)\n' - '\n' - ' Called to implement the built-in functions "complex()", ' - '"int()",\n' - ' "long()", and "float()". Should return a value of the ' - 'appropriate\n' - ' type.\n' - '\n' - 'object.__oct__(self)\n' - 'object.__hex__(self)\n' - '\n' - ' Called to implement the built-in functions "oct()" and ' - '"hex()".\n' - ' Should return a string value.\n' - '\n' - 'object.__index__(self)\n' - '\n' - ' Called to implement "operator.index()". Also called ' - 'whenever\n' - ' Python needs an integer object (such as in slicing). ' - 'Must return\n' - ' an integer (int or long).\n' - '\n' - ' New in version 2.5.\n' - '\n' - 'object.__coerce__(self, other)\n' - '\n' - ' Called to implement "mixed-mode" numeric arithmetic. ' - 'Should either\n' - ' return a 2-tuple containing *self* and *other* converted ' - 'to a\n' - ' common numeric type, or "None" if conversion is ' - 'impossible. When\n' - ' the common type would be the type of "other", it is ' - 'sufficient to\n' - ' return "None", since the interpreter will also ask the ' - 'other object\n' - ' to attempt a coercion (but sometimes, if the ' - 'implementation of the\n' - ' other type cannot be changed, it is useful to do the ' - 'conversion to\n' - ' the other type here). A return value of "NotImplemented" ' - 'is\n' - ' equivalent to returning "None".\n' - '\n' - '\n' - 'Coercion rules\n' - '==============\n' - '\n' - 'This section used to document the rules for coercion. As ' - 'the language\n' - 'has evolved, the coercion rules have become hard to ' - 'document\n' - 'precisely; documenting what one version of one particular\n' - 'implementation does is undesirable. Instead, here are some ' - 'informal\n' - 'guidelines regarding coercion. In Python 3, coercion will ' - 'not be\n' - 'supported.\n' - '\n' - '* If the left operand of a % operator is a string or Unicode ' - 'object,\n' - ' no coercion takes place and the string formatting ' - 'operation is\n' - ' invoked instead.\n' - '\n' - '* It is no longer recommended to define a coercion ' - 'operation. Mixed-\n' - " mode operations on types that don't define coercion pass " - 'the\n' - ' original arguments to the operation.\n' - '\n' - '* New-style classes (those derived from "object") never ' - 'invoke the\n' - ' "__coerce__()" method in response to a binary operator; ' - 'the only\n' - ' time "__coerce__()" is invoked is when the built-in ' - 'function\n' - ' "coerce()" is called.\n' - '\n' - '* For most intents and purposes, an operator that returns\n' - ' "NotImplemented" is treated the same as one that is not ' - 'implemented\n' - ' at all.\n' - '\n' - '* Below, "__op__()" and "__rop__()" are used to signify the ' - 'generic\n' - ' method names corresponding to an operator; "__iop__()" is ' - 'used for\n' - ' the corresponding in-place operator. For example, for the ' - 'operator\n' - ' \'"+"\', "__add__()" and "__radd__()" are used for the ' - 'left and right\n' - ' variant of the binary operator, and "__iadd__()" for the ' - 'in-place\n' - ' variant.\n' - '\n' - '* For objects *x* and *y*, first "x.__op__(y)" is tried. If ' - 'this is\n' - ' not implemented or returns "NotImplemented", ' - '"y.__rop__(x)" is\n' - ' tried. If this is also not implemented or returns ' - '"NotImplemented",\n' - ' a "TypeError" exception is raised. But see the following ' - 'exception:\n' - '\n' - '* Exception to the previous item: if the left operand is an ' - 'instance\n' - ' of a built-in type or a new-style class, and the right ' - 'operand is an\n' - ' instance of a proper subclass of that type or class and ' - 'overrides\n' - ' the base\'s "__rop__()" method, the right operand\'s ' - '"__rop__()"\n' - ' method is tried *before* the left operand\'s "__op__()" ' - 'method.\n' - '\n' - ' This is done so that a subclass can completely override ' - 'binary\n' - ' operators. Otherwise, the left operand\'s "__op__()" ' - 'method would\n' - ' always accept the right operand: when an instance of a ' - 'given class\n' - ' is expected, an instance of a subclass of that class is ' - 'always\n' - ' acceptable.\n' - '\n' - '* When either operand type defines a coercion, this coercion ' - 'is\n' - ' called before that type\'s "__op__()" or "__rop__()" ' - 'method is\n' - ' called, but no sooner. If the coercion returns an object ' - 'of a\n' - ' different type for the operand whose coercion is invoked, ' - 'part of\n' - ' the process is redone using the new object.\n' - '\n' - '* When an in-place operator (like \'"+="\') is used, if the ' - 'left\n' - ' operand implements "__iop__()", it is invoked without any ' - 'coercion.\n' - ' When the operation falls back to "__op__()" and/or ' - '"__rop__()", the\n' - ' normal coercion rules apply.\n' - '\n' - '* In "x + y", if *x* is a sequence that implements sequence\n' - ' concatenation, sequence concatenation is invoked.\n' - '\n' - '* In "x * y", if one operand is a sequence that implements ' - 'sequence\n' - ' repetition, and the other is an integer ("int" or "long"), ' - 'sequence\n' - ' repetition is invoked.\n' - '\n' - '* Rich comparisons (implemented by methods "__eq__()" and so ' - 'on)\n' - ' never use coercion. Three-way comparison (implemented by\n' - ' "__cmp__()") does use coercion under the same conditions ' - 'as other\n' - ' binary operations use it.\n' - '\n' - '* In the current implementation, the built-in numeric types ' - '"int",\n' - ' "long", "float", and "complex" do not use coercion. All ' - 'these types\n' - ' implement a "__coerce__()" method, for use by the ' - 'built-in\n' - ' "coerce()" function.\n' - '\n' - ' Changed in version 2.7: The complex type no longer makes ' - 'implicit\n' - ' calls to the "__coerce__()" method for mixed-type binary ' - 'arithmetic\n' - ' operations.\n' - '\n' - '\n' - 'With Statement Context Managers\n' - '===============================\n' - '\n' - 'New in version 2.5.\n' - '\n' - 'A *context manager* is an object that defines the runtime ' - 'context to\n' - 'be established when executing a "with" statement. The ' - 'context manager\n' - 'handles the entry into, and the exit from, the desired ' - 'runtime context\n' - 'for the execution of the block of code. Context managers ' - 'are normally\n' - 'invoked using the "with" statement (described in section The ' - 'with\n' - 'statement), but can also be used by directly invoking their ' - 'methods.\n' - '\n' - 'Typical uses of context managers include saving and ' - 'restoring various\n' - 'kinds of global state, locking and unlocking resources, ' - 'closing opened\n' - 'files, etc.\n' - '\n' - 'For more information on context managers, see Context ' - 'Manager Types.\n' - '\n' - 'object.__enter__(self)\n' - '\n' - ' Enter the runtime context related to this object. The ' - '"with"\n' - " statement will bind this method's return value to the " - 'target(s)\n' - ' specified in the "as" clause of the statement, if any.\n' - '\n' - 'object.__exit__(self, exc_type, exc_value, traceback)\n' - '\n' - ' Exit the runtime context related to this object. The ' - 'parameters\n' - ' describe the exception that caused the context to be ' - 'exited. If the\n' - ' context was exited without an exception, all three ' - 'arguments will\n' - ' be "None".\n' - '\n' - ' If an exception is supplied, and the method wishes to ' - 'suppress the\n' - ' exception (i.e., prevent it from being propagated), it ' - 'should\n' - ' return a true value. Otherwise, the exception will be ' - 'processed\n' - ' normally upon exit from this method.\n' - '\n' - ' Note that "__exit__()" methods should not reraise the ' - 'passed-in\n' - " exception; this is the caller's responsibility.\n" - '\n' - 'See also:\n' - '\n' - ' **PEP 343** - The "with" statement\n' - ' The specification, background, and examples for the ' - 'Python "with"\n' - ' statement.\n' - '\n' - '\n' - 'Special method lookup for old-style classes\n' - '===========================================\n' - '\n' - 'For old-style classes, special methods are always looked up ' - 'in exactly\n' - 'the same way as any other method or attribute. This is the ' - 'case\n' - 'regardless of whether the method is being looked up ' - 'explicitly as in\n' - '"x.__getitem__(i)" or implicitly as in "x[i]".\n' - '\n' - 'This behaviour means that special methods may exhibit ' - 'different\n' - 'behaviour for different instances of a single old-style ' - 'class if the\n' - 'appropriate special attributes are set differently:\n' - '\n' - ' >>> class C:\n' - ' ... pass\n' - ' ...\n' - ' >>> c1 = C()\n' - ' >>> c2 = C()\n' - ' >>> c1.__len__ = lambda: 5\n' - ' >>> c2.__len__ = lambda: 9\n' - ' >>> len(c1)\n' - ' 5\n' - ' >>> len(c2)\n' - ' 9\n' - '\n' - '\n' - 'Special method lookup for new-style classes\n' - '===========================================\n' - '\n' - 'For new-style classes, implicit invocations of special ' - 'methods are\n' - "only guaranteed to work correctly if defined on an object's " - 'type, not\n' - "in the object's instance dictionary. That behaviour is the " - 'reason why\n' - 'the following code raises an exception (unlike the ' - 'equivalent example\n' - 'with old-style classes):\n' - '\n' - ' >>> class C(object):\n' - ' ... pass\n' - ' ...\n' - ' >>> c = C()\n' - ' >>> c.__len__ = lambda: 5\n' - ' >>> len(c)\n' - ' Traceback (most recent call last):\n' - ' File "<stdin>", line 1, in <module>\n' - " TypeError: object of type 'C' has no len()\n" - '\n' - 'The rationale behind this behaviour lies with a number of ' - 'special\n' - 'methods such as "__hash__()" and "__repr__()" that are ' - 'implemented by\n' - 'all objects, including type objects. If the implicit lookup ' - 'of these\n' - 'methods used the conventional lookup process, they would ' - 'fail when\n' - 'invoked on the type object itself:\n' - '\n' - ' >>> 1 .__hash__() == hash(1)\n' - ' True\n' - ' >>> int.__hash__() == hash(int)\n' - ' Traceback (most recent call last):\n' - ' File "<stdin>", line 1, in <module>\n' - " TypeError: descriptor '__hash__' of 'int' object needs an " - 'argument\n' - '\n' - 'Incorrectly attempting to invoke an unbound method of a ' - 'class in this\n' - "way is sometimes referred to as 'metaclass confusion', and " - 'is avoided\n' - 'by bypassing the instance when looking up special methods:\n' - '\n' - ' >>> type(1).__hash__(1) == hash(1)\n' - ' True\n' - ' >>> type(int).__hash__(int) == hash(int)\n' - ' True\n' - '\n' - 'In addition to bypassing any instance attributes in the ' - 'interest of\n' - 'correctness, implicit special method lookup generally also ' - 'bypasses\n' - 'the "__getattribute__()" method even of the object\'s ' - 'metaclass:\n' - '\n' - ' >>> class Meta(type):\n' - ' ... def __getattribute__(*args):\n' - ' ... print "Metaclass getattribute invoked"\n' - ' ... return type.__getattribute__(*args)\n' - ' ...\n' - ' >>> class C(object):\n' - ' ... __metaclass__ = Meta\n' - ' ... def __len__(self):\n' - ' ... return 10\n' - ' ... def __getattribute__(*args):\n' - ' ... print "Class getattribute invoked"\n' - ' ... return object.__getattribute__(*args)\n' - ' ...\n' - ' >>> c = C()\n' - ' >>> c.__len__() # Explicit lookup via ' - 'instance\n' - ' Class getattribute invoked\n' - ' 10\n' - ' >>> type(c).__len__(c) # Explicit lookup via ' - 'type\n' - ' Metaclass getattribute invoked\n' - ' 10\n' - ' >>> len(c) # Implicit lookup\n' - ' 10\n' - '\n' - 'Bypassing the "__getattribute__()" machinery in this fashion ' - 'provides\n' - 'significant scope for speed optimisations within the ' - 'interpreter, at\n' - 'the cost of some flexibility in the handling of special ' - 'methods (the\n' - 'special method *must* be set on the class object itself in ' - 'order to be\n' - 'consistently invoked by the interpreter).\n' - '\n' - '-[ Footnotes ]-\n' - '\n' - "[1] It *is* possible in some cases to change an object's " - 'type,\n' - " under certain controlled conditions. It generally isn't " - 'a good\n' - ' idea though, since it can lead to some very strange ' - 'behaviour if\n' - ' it is handled incorrectly.\n' - '\n' - '[2] For operands of the same type, it is assumed that if the ' - 'non-\n' - ' reflected method (such as "__add__()") fails the ' - 'operation is not\n' - ' supported, which is why the reflected method is not ' - 'called.\n', - 'string-methods': '\n' - 'String Methods\n' - '**************\n' - '\n' - 'Below are listed the string methods which both 8-bit ' - 'strings and\n' - 'Unicode objects support. Some of them are also available ' - 'on\n' - '"bytearray" objects.\n' - '\n' - "In addition, Python's strings support the sequence type " - 'methods\n' - 'described in the Sequence Types --- str, unicode, list, ' - 'tuple,\n' - 'bytearray, buffer, xrange section. To output formatted ' - 'strings use\n' - 'template strings or the "%" operator described in the ' - 'String\n' - 'Formatting Operations section. Also, see the "re" module ' - 'for string\n' - 'functions based on regular expressions.\n' - '\n' - 'str.capitalize()\n' - '\n' - ' Return a copy of the string with its first character ' - 'capitalized\n' - ' and the rest lowercased.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.center(width[, fillchar])\n' - '\n' - ' Return centered in a string of length *width*. Padding ' - 'is done\n' - ' using the specified *fillchar* (default is a space).\n' - '\n' - ' Changed in version 2.4: Support for the *fillchar* ' - 'argument.\n' - '\n' - 'str.count(sub[, start[, end]])\n' - '\n' - ' Return the number of non-overlapping occurrences of ' - 'substring *sub*\n' - ' in the range [*start*, *end*]. Optional arguments ' - '*start* and\n' - ' *end* are interpreted as in slice notation.\n' - '\n' - 'str.decode([encoding[, errors]])\n' - '\n' - ' Decodes the string using the codec registered for ' - '*encoding*.\n' - ' *encoding* defaults to the default string encoding. ' - '*errors* may\n' - ' be given to set a different error handling scheme. The ' - 'default is\n' - ' "\'strict\'", meaning that encoding errors raise ' - '"UnicodeError".\n' - ' Other possible values are "\'ignore\'", "\'replace\'" ' - 'and any other\n' - ' name registered via "codecs.register_error()", see ' - 'section Codec\n' - ' Base Classes.\n' - '\n' - ' New in version 2.2.\n' - '\n' - ' Changed in version 2.3: Support for other error ' - 'handling schemes\n' - ' added.\n' - '\n' - ' Changed in version 2.7: Support for keyword arguments ' - 'added.\n' - '\n' - 'str.encode([encoding[, errors]])\n' - '\n' - ' Return an encoded version of the string. Default ' - 'encoding is the\n' - ' current default string encoding. *errors* may be given ' - 'to set a\n' - ' different error handling scheme. The default for ' - '*errors* is\n' - ' "\'strict\'", meaning that encoding errors raise a ' - '"UnicodeError".\n' - ' Other possible values are "\'ignore\'", "\'replace\'",\n' - ' "\'xmlcharrefreplace\'", "\'backslashreplace\'" and any ' - 'other name\n' - ' registered via "codecs.register_error()", see section ' - 'Codec Base\n' - ' Classes. For a list of possible encodings, see section ' - 'Standard\n' - ' Encodings.\n' - '\n' - ' New in version 2.0.\n' - '\n' - ' Changed in version 2.3: Support for ' - '"\'xmlcharrefreplace\'" and\n' - ' "\'backslashreplace\'" and other error handling schemes ' - 'added.\n' - '\n' - ' Changed in version 2.7: Support for keyword arguments ' - 'added.\n' - '\n' - 'str.endswith(suffix[, start[, end]])\n' - '\n' - ' Return "True" if the string ends with the specified ' - '*suffix*,\n' - ' otherwise return "False". *suffix* can also be a tuple ' - 'of suffixes\n' - ' to look for. With optional *start*, test beginning at ' - 'that\n' - ' position. With optional *end*, stop comparing at that ' - 'position.\n' - '\n' - ' Changed in version 2.5: Accept tuples as *suffix*.\n' - '\n' - 'str.expandtabs([tabsize])\n' - '\n' - ' Return a copy of the string where all tab characters ' - 'are replaced\n' - ' by one or more spaces, depending on the current column ' - 'and the\n' - ' given tab size. Tab positions occur every *tabsize* ' - 'characters\n' - ' (default is 8, giving tab positions at columns 0, 8, 16 ' - 'and so on).\n' - ' To expand the string, the current column is set to zero ' - 'and the\n' - ' string is examined character by character. If the ' - 'character is a\n' - ' tab ("\\t"), one or more space characters are inserted ' - 'in the result\n' - ' until the current column is equal to the next tab ' - 'position. (The\n' - ' tab character itself is not copied.) If the character ' - 'is a newline\n' - ' ("\\n") or return ("\\r"), it is copied and the current ' - 'column is\n' - ' reset to zero. Any other character is copied unchanged ' - 'and the\n' - ' current column is incremented by one regardless of how ' - 'the\n' - ' character is represented when printed.\n' - '\n' - " >>> '01\\t012\\t0123\\t01234'.expandtabs()\n" - " '01 012 0123 01234'\n" - " >>> '01\\t012\\t0123\\t01234'.expandtabs(4)\n" - " '01 012 0123 01234'\n" - '\n' - 'str.find(sub[, start[, end]])\n' - '\n' - ' Return the lowest index in the string where substring ' - '*sub* is\n' - ' found within the slice "s[start:end]". Optional ' - 'arguments *start*\n' - ' and *end* are interpreted as in slice notation. Return ' - '"-1" if\n' - ' *sub* is not found.\n' - '\n' - ' Note: The "find()" method should be used only if you ' - 'need to know\n' - ' the position of *sub*. To check if *sub* is a ' - 'substring or not,\n' - ' use the "in" operator:\n' - '\n' - " >>> 'Py' in 'Python'\n" - ' True\n' - '\n' - 'str.format(*args, **kwargs)\n' - '\n' - ' Perform a string formatting operation. The string on ' - 'which this\n' - ' method is called can contain literal text or ' - 'replacement fields\n' - ' delimited by braces "{}". Each replacement field ' - 'contains either\n' - ' the numeric index of a positional argument, or the name ' - 'of a\n' - ' keyword argument. Returns a copy of the string where ' - 'each\n' - ' replacement field is replaced with the string value of ' - 'the\n' - ' corresponding argument.\n' - '\n' - ' >>> "The sum of 1 + 2 is {0}".format(1+2)\n' - " 'The sum of 1 + 2 is 3'\n" - '\n' - ' See Format String Syntax for a description of the ' - 'various\n' - ' formatting options that can be specified in format ' - 'strings.\n' - '\n' - ' This method of string formatting is the new standard in ' - 'Python 3,\n' - ' and should be preferred to the "%" formatting described ' - 'in String\n' - ' Formatting Operations in new code.\n' - '\n' - ' New in version 2.6.\n' - '\n' - 'str.index(sub[, start[, end]])\n' - '\n' - ' Like "find()", but raise "ValueError" when the ' - 'substring is not\n' - ' found.\n' - '\n' - 'str.isalnum()\n' - '\n' - ' Return true if all characters in the string are ' - 'alphanumeric and\n' - ' there is at least one character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.isalpha()\n' - '\n' - ' Return true if all characters in the string are ' - 'alphabetic and\n' - ' there is at least one character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.isdigit()\n' - '\n' - ' Return true if all characters in the string are digits ' - 'and there is\n' - ' at least one character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.islower()\n' - '\n' - ' Return true if all cased characters [4] in the string ' - 'are lowercase\n' - ' and there is at least one cased character, false ' - 'otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.isspace()\n' - '\n' - ' Return true if there are only whitespace characters in ' - 'the string\n' - ' and there is at least one character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.istitle()\n' - '\n' - ' Return true if the string is a titlecased string and ' - 'there is at\n' - ' least one character, for example uppercase characters ' - 'may only\n' - ' follow uncased characters and lowercase characters only ' - 'cased ones.\n' - ' Return false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.isupper()\n' - '\n' - ' Return true if all cased characters [4] in the string ' - 'are uppercase\n' - ' and there is at least one cased character, false ' - 'otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.join(iterable)\n' - '\n' - ' Return a string which is the concatenation of the ' - 'strings in\n' - ' *iterable*. A "TypeError" will be raised if there are ' - 'any non-\n' - ' string values in *iterable*, including "bytes" ' - 'objects. The\n' - ' separator between elements is the string providing this ' - 'method.\n' - '\n' - 'str.ljust(width[, fillchar])\n' - '\n' - ' Return the string left justified in a string of length ' - '*width*.\n' - ' Padding is done using the specified *fillchar* (default ' - 'is a\n' - ' space). The original string is returned if *width* is ' - 'less than or\n' - ' equal to "len(s)".\n' - '\n' - ' Changed in version 2.4: Support for the *fillchar* ' - 'argument.\n' - '\n' - 'str.lower()\n' - '\n' - ' Return a copy of the string with all the cased ' - 'characters [4]\n' - ' converted to lowercase.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.lstrip([chars])\n' - '\n' - ' Return a copy of the string with leading characters ' - 'removed. The\n' - ' *chars* argument is a string specifying the set of ' - 'characters to be\n' - ' removed. If omitted or "None", the *chars* argument ' - 'defaults to\n' - ' removing whitespace. The *chars* argument is not a ' - 'prefix; rather,\n' - ' all combinations of its values are stripped:\n' - '\n' - " >>> ' spacious '.lstrip()\n" - " 'spacious '\n" - " >>> 'www.example.com'.lstrip('cmowz.')\n" - " 'example.com'\n" - '\n' - ' Changed in version 2.2.2: Support for the *chars* ' - 'argument.\n' - '\n' - 'str.partition(sep)\n' - '\n' - ' Split the string at the first occurrence of *sep*, and ' - 'return a\n' - ' 3-tuple containing the part before the separator, the ' - 'separator\n' - ' itself, and the part after the separator. If the ' - 'separator is not\n' - ' found, return a 3-tuple containing the string itself, ' - 'followed by\n' - ' two empty strings.\n' - '\n' - ' New in version 2.5.\n' - '\n' - 'str.replace(old, new[, count])\n' - '\n' - ' Return a copy of the string with all occurrences of ' - 'substring *old*\n' - ' replaced by *new*. If the optional argument *count* is ' - 'given, only\n' - ' the first *count* occurrences are replaced.\n' - '\n' - 'str.rfind(sub[, start[, end]])\n' - '\n' - ' Return the highest index in the string where substring ' - '*sub* is\n' - ' found, such that *sub* is contained within ' - '"s[start:end]".\n' - ' Optional arguments *start* and *end* are interpreted as ' - 'in slice\n' - ' notation. Return "-1" on failure.\n' - '\n' - 'str.rindex(sub[, start[, end]])\n' - '\n' - ' Like "rfind()" but raises "ValueError" when the ' - 'substring *sub* is\n' - ' not found.\n' - '\n' - 'str.rjust(width[, fillchar])\n' - '\n' - ' Return the string right justified in a string of length ' - '*width*.\n' - ' Padding is done using the specified *fillchar* (default ' - 'is a\n' - ' space). The original string is returned if *width* is ' - 'less than or\n' - ' equal to "len(s)".\n' - '\n' - ' Changed in version 2.4: Support for the *fillchar* ' - 'argument.\n' - '\n' - 'str.rpartition(sep)\n' - '\n' - ' Split the string at the last occurrence of *sep*, and ' - 'return a\n' - ' 3-tuple containing the part before the separator, the ' - 'separator\n' - ' itself, and the part after the separator. If the ' - 'separator is not\n' - ' found, return a 3-tuple containing two empty strings, ' - 'followed by\n' - ' the string itself.\n' - '\n' - ' New in version 2.5.\n' - '\n' - 'str.rsplit([sep[, maxsplit]])\n' - '\n' - ' Return a list of the words in the string, using *sep* ' - 'as the\n' - ' delimiter string. If *maxsplit* is given, at most ' - '*maxsplit* splits\n' - ' are done, the *rightmost* ones. If *sep* is not ' - 'specified or\n' - ' "None", any whitespace string is a separator. Except ' - 'for splitting\n' - ' from the right, "rsplit()" behaves like "split()" which ' - 'is\n' - ' described in detail below.\n' - '\n' - ' New in version 2.4.\n' - '\n' - 'str.rstrip([chars])\n' - '\n' - ' Return a copy of the string with trailing characters ' - 'removed. The\n' - ' *chars* argument is a string specifying the set of ' - 'characters to be\n' - ' removed. If omitted or "None", the *chars* argument ' - 'defaults to\n' - ' removing whitespace. The *chars* argument is not a ' - 'suffix; rather,\n' - ' all combinations of its values are stripped:\n' - '\n' - " >>> ' spacious '.rstrip()\n" - " ' spacious'\n" - " >>> 'mississippi'.rstrip('ipz')\n" - " 'mississ'\n" - '\n' - ' Changed in version 2.2.2: Support for the *chars* ' - 'argument.\n' - '\n' - 'str.split([sep[, maxsplit]])\n' - '\n' - ' Return a list of the words in the string, using *sep* ' - 'as the\n' - ' delimiter string. If *maxsplit* is given, at most ' - '*maxsplit*\n' - ' splits are done (thus, the list will have at most ' - '"maxsplit+1"\n' - ' elements). If *maxsplit* is not specified or "-1", ' - 'then there is\n' - ' no limit on the number of splits (all possible splits ' - 'are made).\n' - '\n' - ' If *sep* is given, consecutive delimiters are not ' - 'grouped together\n' - ' and are deemed to delimit empty strings (for example,\n' - ' "\'1,,2\'.split(\',\')" returns "[\'1\', \'\', ' - '\'2\']"). The *sep* argument\n' - ' may consist of multiple characters (for example,\n' - ' "\'1<>2<>3\'.split(\'<>\')" returns "[\'1\', \'2\', ' - '\'3\']"). Splitting an\n' - ' empty string with a specified separator returns ' - '"[\'\']".\n' - '\n' - ' If *sep* is not specified or is "None", a different ' - 'splitting\n' - ' algorithm is applied: runs of consecutive whitespace ' - 'are regarded\n' - ' as a single separator, and the result will contain no ' - 'empty strings\n' - ' at the start or end if the string has leading or ' - 'trailing\n' - ' whitespace. Consequently, splitting an empty string or ' - 'a string\n' - ' consisting of just whitespace with a "None" separator ' - 'returns "[]".\n' - '\n' - ' For example, "\' 1 2 3 \'.split()" returns "[\'1\', ' - '\'2\', \'3\']", and\n' - ' "\' 1 2 3 \'.split(None, 1)" returns "[\'1\', ' - '\'2 3 \']".\n' - '\n' - 'str.splitlines([keepends])\n' - '\n' - ' Return a list of the lines in the string, breaking at ' - 'line\n' - ' boundaries. This method uses the *universal newlines* ' - 'approach to\n' - ' splitting lines. Line breaks are not included in the ' - 'resulting list\n' - ' unless *keepends* is given and true.\n' - '\n' - ' Python recognizes ""\\r"", ""\\n"", and ""\\r\\n"" as ' - 'line boundaries\n' - ' for 8-bit strings.\n' - '\n' - ' For example:\n' - '\n' - " >>> 'ab c\\n\\nde fg\\rkl\\r\\n'.splitlines()\n" - " ['ab c', '', 'de fg', 'kl']\n" - " >>> 'ab c\\n\\nde fg\\rkl\\r\\n'.splitlines(True)\n" - " ['ab c\\n', '\\n', 'de fg\\r', 'kl\\r\\n']\n" - '\n' - ' Unlike "split()" when a delimiter string *sep* is ' - 'given, this\n' - ' method returns an empty list for the empty string, and ' - 'a terminal\n' - ' line break does not result in an extra line:\n' - '\n' - ' >>> "".splitlines()\n' - ' []\n' - ' >>> "One line\\n".splitlines()\n' - " ['One line']\n" - '\n' - ' For comparison, "split(\'\\n\')" gives:\n' - '\n' - " >>> ''.split('\\n')\n" - " ['']\n" - " >>> 'Two lines\\n'.split('\\n')\n" - " ['Two lines', '']\n" - '\n' - 'unicode.splitlines([keepends])\n' - '\n' - ' Return a list of the lines in the string, like ' - '"str.splitlines()".\n' - ' However, the Unicode method splits on the following ' - 'line\n' - ' boundaries, which are a superset of the *universal ' - 'newlines*\n' - ' recognized for 8-bit strings.\n' - '\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | Representation | ' - 'Description |\n' - ' ' - '+=========================+===============================+\n' - ' | "\\n" | Line ' - 'Feed |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\r" | Carriage ' - 'Return |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\r\\n" | Carriage Return + Line ' - 'Feed |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\v" or "\\x0b" | Line ' - 'Tabulation |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\f" or "\\x0c" | Form ' - 'Feed |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\x1c" | File ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\x1d" | Group ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\x1e" | Record ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\x85" | Next Line (C1 Control ' - 'Code) |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\u2028" | Line ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - ' | "\\u2029" | Paragraph ' - 'Separator |\n' - ' ' - '+-------------------------+-------------------------------+\n' - '\n' - ' Changed in version 2.7: "\\v" and "\\f" added to list ' - 'of line\n' - ' boundaries.\n' - '\n' - 'str.startswith(prefix[, start[, end]])\n' - '\n' - ' Return "True" if string starts with the *prefix*, ' - 'otherwise return\n' - ' "False". *prefix* can also be a tuple of prefixes to ' - 'look for.\n' - ' With optional *start*, test string beginning at that ' - 'position.\n' - ' With optional *end*, stop comparing string at that ' - 'position.\n' - '\n' - ' Changed in version 2.5: Accept tuples as *prefix*.\n' - '\n' - 'str.strip([chars])\n' - '\n' - ' Return a copy of the string with the leading and ' - 'trailing\n' - ' characters removed. The *chars* argument is a string ' - 'specifying the\n' - ' set of characters to be removed. If omitted or "None", ' - 'the *chars*\n' - ' argument defaults to removing whitespace. The *chars* ' - 'argument is\n' - ' not a prefix or suffix; rather, all combinations of its ' - 'values are\n' - ' stripped:\n' - '\n' - " >>> ' spacious '.strip()\n" - " 'spacious'\n" - " >>> 'www.example.com'.strip('cmowz.')\n" - " 'example'\n" - '\n' - ' Changed in version 2.2.2: Support for the *chars* ' - 'argument.\n' - '\n' - 'str.swapcase()\n' - '\n' - ' Return a copy of the string with uppercase characters ' - 'converted to\n' - ' lowercase and vice versa.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.title()\n' - '\n' - ' Return a titlecased version of the string where words ' - 'start with an\n' - ' uppercase character and the remaining characters are ' - 'lowercase.\n' - '\n' - ' The algorithm uses a simple language-independent ' - 'definition of a\n' - ' word as groups of consecutive letters. The definition ' - 'works in\n' - ' many contexts but it means that apostrophes in ' - 'contractions and\n' - ' possessives form word boundaries, which may not be the ' - 'desired\n' - ' result:\n' - '\n' - ' >>> "they\'re bill\'s friends from the UK".title()\n' - ' "They\'Re Bill\'S Friends From The Uk"\n' - '\n' - ' A workaround for apostrophes can be constructed using ' - 'regular\n' - ' expressions:\n' - '\n' - ' >>> import re\n' - ' >>> def titlecase(s):\n' - ' ... return re.sub(r"[A-Za-z]+(\'[A-Za-z]+)?",\n' - ' ... lambda mo: ' - 'mo.group(0)[0].upper() +\n' - ' ... ' - 'mo.group(0)[1:].lower(),\n' - ' ... s)\n' - ' ...\n' - ' >>> titlecase("they\'re bill\'s friends.")\n' - ' "They\'re Bill\'s Friends."\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.translate(table[, deletechars])\n' - '\n' - ' Return a copy of the string where all characters ' - 'occurring in the\n' - ' optional argument *deletechars* are removed, and the ' - 'remaining\n' - ' characters have been mapped through the given ' - 'translation table,\n' - ' which must be a string of length 256.\n' - '\n' - ' You can use the "maketrans()" helper function in the ' - '"string"\n' - ' module to create a translation table. For string ' - 'objects, set the\n' - ' *table* argument to "None" for translations that only ' - 'delete\n' - ' characters:\n' - '\n' - " >>> 'read this short text'.translate(None, 'aeiou')\n" - " 'rd ths shrt txt'\n" - '\n' - ' New in version 2.6: Support for a "None" *table* ' - 'argument.\n' - '\n' - ' For Unicode objects, the "translate()" method does not ' - 'accept the\n' - ' optional *deletechars* argument. Instead, it returns a ' - 'copy of the\n' - ' *s* where all characters have been mapped through the ' - 'given\n' - ' translation table which must be a mapping of Unicode ' - 'ordinals to\n' - ' Unicode ordinals, Unicode strings or "None". Unmapped ' - 'characters\n' - ' are left untouched. Characters mapped to "None" are ' - 'deleted. Note,\n' - ' a more flexible approach is to create a custom ' - 'character mapping\n' - ' codec using the "codecs" module (see "encodings.cp1251" ' - 'for an\n' - ' example).\n' - '\n' - 'str.upper()\n' - '\n' - ' Return a copy of the string with all the cased ' - 'characters [4]\n' - ' converted to uppercase. Note that ' - '"str.upper().isupper()" might be\n' - ' "False" if "s" contains uncased characters or if the ' - 'Unicode\n' - ' category of the resulting character(s) is not "Lu" ' - '(Letter,\n' - ' uppercase), but e.g. "Lt" (Letter, titlecase).\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.zfill(width)\n' - '\n' - ' Return the numeric string left filled with zeros in a ' - 'string of\n' - ' length *width*. A sign prefix is handled correctly. ' - 'The original\n' - ' string is returned if *width* is less than or equal to ' - '"len(s)".\n' - '\n' - ' New in version 2.2.2.\n' - '\n' - 'The following methods are present only on unicode ' - 'objects:\n' - '\n' - 'unicode.isnumeric()\n' - '\n' - ' Return "True" if there are only numeric characters in ' - 'S, "False"\n' - ' otherwise. Numeric characters include digit characters, ' - 'and all\n' - ' characters that have the Unicode numeric value ' - 'property, e.g.\n' - ' U+2155, VULGAR FRACTION ONE FIFTH.\n' - '\n' - 'unicode.isdecimal()\n' - '\n' - ' Return "True" if there are only decimal characters in ' - 'S, "False"\n' - ' otherwise. Decimal characters include digit characters, ' - 'and all\n' - ' characters that can be used to form decimal-radix ' - 'numbers, e.g.\n' - ' U+0660, ARABIC-INDIC DIGIT ZERO.\n', - 'strings': '\n' - 'String literals\n' - '***************\n' - '\n' - 'String literals are described by the following lexical ' - 'definitions:\n' - '\n' - ' stringliteral ::= [stringprefix](shortstring | longstring)\n' - ' stringprefix ::= "r" | "u" | "ur" | "R" | "U" | "UR" | "Ur" ' - '| "uR"\n' - ' | "b" | "B" | "br" | "Br" | "bR" | "BR"\n' - ' shortstring ::= "\'" shortstringitem* "\'" | \'"\' ' - 'shortstringitem* \'"\'\n' - ' longstring ::= "\'\'\'" longstringitem* "\'\'\'"\n' - ' | \'"""\' longstringitem* \'"""\'\n' - ' shortstringitem ::= shortstringchar | escapeseq\n' - ' longstringitem ::= longstringchar | escapeseq\n' - ' shortstringchar ::= <any source character except "\\" or ' - 'newline or the quote>\n' - ' longstringchar ::= <any source character except "\\">\n' - ' escapeseq ::= "\\" <any ASCII character>\n' - '\n' - 'One syntactic restriction not indicated by these productions is ' - 'that\n' - 'whitespace is not allowed between the "stringprefix" and the rest ' - 'of\n' - 'the string literal. The source character set is defined by the\n' - 'encoding declaration; it is ASCII if no encoding declaration is ' - 'given\n' - 'in the source file; see section Encoding declarations.\n' - '\n' - 'In plain English: String literals can be enclosed in matching ' - 'single\n' - 'quotes ("\'") or double quotes ("""). They can also be enclosed ' - 'in\n' - 'matching groups of three single or double quotes (these are ' - 'generally\n' - 'referred to as *triple-quoted strings*). The backslash ("\\")\n' - 'character is used to escape characters that otherwise have a ' - 'special\n' - 'meaning, such as newline, backslash itself, or the quote ' - 'character.\n' - 'String literals may optionally be prefixed with a letter "\'r\'" ' - 'or\n' - '"\'R\'"; such strings are called *raw strings* and use different ' - 'rules\n' - 'for interpreting backslash escape sequences. A prefix of "\'u\'" ' - 'or\n' - '"\'U\'" makes the string a Unicode string. Unicode strings use ' - 'the\n' - 'Unicode character set as defined by the Unicode Consortium and ' - 'ISO\n' - '10646. Some additional escape sequences, described below, are\n' - 'available in Unicode strings. A prefix of "\'b\'" or "\'B\'" is ' - 'ignored in\n' - 'Python 2; it indicates that the literal should become a bytes ' - 'literal\n' - 'in Python 3 (e.g. when code is automatically converted with ' - '2to3). A\n' - '"\'u\'" or "\'b\'" prefix may be followed by an "\'r\'" prefix.\n' - '\n' - 'In triple-quoted strings, unescaped newlines and quotes are ' - 'allowed\n' - '(and are retained), except that three unescaped quotes in a row\n' - 'terminate the string. (A "quote" is the character used to open ' - 'the\n' - 'string, i.e. either "\'" or """.)\n' - '\n' - 'Unless an "\'r\'" or "\'R\'" prefix is present, escape sequences ' - 'in\n' - 'strings are interpreted according to rules similar to those used ' - 'by\n' - 'Standard C. The recognized escape sequences are:\n' - '\n' - '+-------------------+-----------------------------------+---------+\n' - '| Escape Sequence | Meaning | Notes ' - '|\n' - '+===================+===================================+=========+\n' - '| "\\newline" | Ignored ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\\\" | Backslash ("\\") ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\\'" | Single quote ("\'") ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\"" | Double quote (""") ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\a" | ASCII Bell (BEL) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\b" | ASCII Backspace (BS) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\f" | ASCII Formfeed (FF) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\n" | ASCII Linefeed (LF) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\N{name}" | Character named *name* in the ' - '| |\n' - '| | Unicode database (Unicode only) | ' - '|\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\r" | ASCII Carriage Return (CR) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\t" | ASCII Horizontal Tab (TAB) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\uxxxx" | Character with 16-bit hex value | ' - '(1) |\n' - '| | *xxxx* (Unicode only) | ' - '|\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\Uxxxxxxxx" | Character with 32-bit hex value | ' - '(2) |\n' - '| | *xxxxxxxx* (Unicode only) | ' - '|\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\v" | ASCII Vertical Tab (VT) ' - '| |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\ooo" | Character with octal value *ooo* | ' - '(3,5) |\n' - '+-------------------+-----------------------------------+---------+\n' - '| "\\xhh" | Character with hex value *hh* | ' - '(4,5) |\n' - '+-------------------+-----------------------------------+---------+\n' - '\n' - 'Notes:\n' - '\n' - '1. Individual code units which form parts of a surrogate pair ' - 'can\n' - ' be encoded using this escape sequence.\n' - '\n' - '2. Any Unicode character can be encoded this way, but characters\n' - ' outside the Basic Multilingual Plane (BMP) will be encoded ' - 'using a\n' - ' surrogate pair if Python is compiled to use 16-bit code units ' - '(the\n' - ' default).\n' - '\n' - '3. As in Standard C, up to three octal digits are accepted.\n' - '\n' - '4. Unlike in Standard C, exactly two hex digits are required.\n' - '\n' - '5. In a string literal, hexadecimal and octal escapes denote the\n' - ' byte with the given value; it is not necessary that the byte\n' - ' encodes a character in the source character set. In a Unicode\n' - ' literal, these escapes denote a Unicode character with the ' - 'given\n' - ' value.\n' - '\n' - 'Unlike Standard C, all unrecognized escape sequences are left in ' - 'the\n' - 'string unchanged, i.e., *the backslash is left in the string*. ' - '(This\n' - 'behavior is useful when debugging: if an escape sequence is ' - 'mistyped,\n' - 'the resulting output is more easily recognized as broken.) It is ' - 'also\n' - 'important to note that the escape sequences marked as "(Unicode ' - 'only)"\n' - 'in the table above fall into the category of unrecognized escapes ' - 'for\n' - 'non-Unicode string literals.\n' - '\n' - 'When an "\'r\'" or "\'R\'" prefix is present, a character ' - 'following a\n' - 'backslash is included in the string without change, and *all\n' - 'backslashes are left in the string*. For example, the string ' - 'literal\n' - '"r"\\n"" consists of two characters: a backslash and a lowercase ' - '"\'n\'".\n' - 'String quotes can be escaped with a backslash, but the backslash\n' - 'remains in the string; for example, "r"\\""" is a valid string ' - 'literal\n' - 'consisting of two characters: a backslash and a double quote; ' - '"r"\\""\n' - 'is not a valid string literal (even a raw string cannot end in an ' - 'odd\n' - 'number of backslashes). Specifically, *a raw string cannot end ' - 'in a\n' - 'single backslash* (since the backslash would escape the ' - 'following\n' - 'quote character). Note also that a single backslash followed by ' - 'a\n' - 'newline is interpreted as those two characters as part of the ' - 'string,\n' - '*not* as a line continuation.\n' - '\n' - 'When an "\'r\'" or "\'R\'" prefix is used in conjunction with a ' - '"\'u\'" or\n' - '"\'U\'" prefix, then the "\\uXXXX" and "\\UXXXXXXXX" escape ' - 'sequences are\n' - 'processed while *all other backslashes are left in the string*. ' - 'For\n' - 'example, the string literal "ur"\\u0062\\n"" consists of three ' - 'Unicode\n' - "characters: 'LATIN SMALL LETTER B', 'REVERSE SOLIDUS', and " - "'LATIN\n" - "SMALL LETTER N'. Backslashes can be escaped with a preceding\n" - 'backslash; however, both remain in the string. As a result, ' - '"\\uXXXX"\n' - 'escape sequences are only recognized when there are an odd number ' - 'of\n' - 'backslashes.\n', - 'subscriptions': '\n' - 'Subscriptions\n' - '*************\n' - '\n' - 'A subscription selects an item of a sequence (string, tuple ' - 'or list)\n' - 'or mapping (dictionary) object:\n' - '\n' - ' subscription ::= primary "[" expression_list "]"\n' - '\n' - 'The primary must evaluate to an object of a sequence or ' - 'mapping type.\n' - '\n' - 'If the primary is a mapping, the expression list must ' - 'evaluate to an\n' - 'object whose value is one of the keys of the mapping, and ' - 'the\n' - 'subscription selects the value in the mapping that ' - 'corresponds to that\n' - 'key. (The expression list is a tuple except if it has ' - 'exactly one\n' - 'item.)\n' - '\n' - 'If the primary is a sequence, the expression (list) must ' - 'evaluate to a\n' - 'plain integer. If this value is negative, the length of ' - 'the sequence\n' - 'is added to it (so that, e.g., "x[-1]" selects the last ' - 'item of "x".)\n' - 'The resulting value must be a nonnegative integer less than ' - 'the number\n' - 'of items in the sequence, and the subscription selects the ' - 'item whose\n' - 'index is that value (counting from zero).\n' - '\n' - "A string's items are characters. A character is not a " - 'separate data\n' - 'type but a string of exactly one character.\n', - 'truth': '\n' - 'Truth Value Testing\n' - '*******************\n' - '\n' - 'Any object can be tested for truth value, for use in an "if" or\n' - '"while" condition or as operand of the Boolean operations below. ' - 'The\n' - 'following values are considered false:\n' - '\n' - '* "None"\n' - '\n' - '* "False"\n' - '\n' - '* zero of any numeric type, for example, "0", "0L", "0.0", "0j".\n' - '\n' - '* any empty sequence, for example, "\'\'", "()", "[]".\n' - '\n' - '* any empty mapping, for example, "{}".\n' - '\n' - '* instances of user-defined classes, if the class defines a\n' - ' "__nonzero__()" or "__len__()" method, when that method returns ' - 'the\n' - ' integer zero or "bool" value "False". [1]\n' - '\n' - 'All other values are considered true --- so objects of many types ' - 'are\n' - 'always true.\n' - '\n' - 'Operations and built-in functions that have a Boolean result ' - 'always\n' - 'return "0" or "False" for false and "1" or "True" for true, unless\n' - 'otherwise stated. (Important exception: the Boolean operations ' - '"or"\n' - 'and "and" always return one of their operands.)\n', - 'try': '\n' - 'The "try" statement\n' - '*******************\n' - '\n' - 'The "try" statement specifies exception handlers and/or cleanup code\n' - 'for a group of statements:\n' - '\n' - ' try_stmt ::= try1_stmt | try2_stmt\n' - ' try1_stmt ::= "try" ":" suite\n' - ' ("except" [expression [("as" | ",") identifier]] ":" ' - 'suite)+\n' - ' ["else" ":" suite]\n' - ' ["finally" ":" suite]\n' - ' try2_stmt ::= "try" ":" suite\n' - ' "finally" ":" suite\n' - '\n' - 'Changed in version 2.5: In previous versions of Python,\n' - '"try"..."except"..."finally" did not work. "try"..."except" had to ' - 'be\n' - 'nested in "try"..."finally".\n' - '\n' - 'The "except" clause(s) specify one or more exception handlers. When ' - 'no\n' - 'exception occurs in the "try" clause, no exception handler is\n' - 'executed. When an exception occurs in the "try" suite, a search for ' - 'an\n' - 'exception handler is started. This search inspects the except ' - 'clauses\n' - 'in turn until one is found that matches the exception. An ' - 'expression-\n' - 'less except clause, if present, must be last; it matches any\n' - 'exception. For an except clause with an expression, that expression\n' - 'is evaluated, and the clause matches the exception if the resulting\n' - 'object is "compatible" with the exception. An object is compatible\n' - 'with an exception if it is the class or a base class of the ' - 'exception\n' - 'object, or a tuple containing an item compatible with the exception.\n' - '\n' - 'If no except clause matches the exception, the search for an ' - 'exception\n' - 'handler continues in the surrounding code and on the invocation ' - 'stack.\n' - '[1]\n' - '\n' - 'If the evaluation of an expression in the header of an except clause\n' - 'raises an exception, the original search for a handler is canceled ' - 'and\n' - 'a search starts for the new exception in the surrounding code and on\n' - 'the call stack (it is treated as if the entire "try" statement ' - 'raised\n' - 'the exception).\n' - '\n' - 'When a matching except clause is found, the exception is assigned to\n' - 'the target specified in that except clause, if present, and the ' - 'except\n' - "clause's suite is executed. All except clauses must have an\n" - 'executable block. When the end of this block is reached, execution\n' - 'continues normally after the entire try statement. (This means that\n' - 'if two nested handlers exist for the same exception, and the ' - 'exception\n' - 'occurs in the try clause of the inner handler, the outer handler ' - 'will\n' - 'not handle the exception.)\n' - '\n' - "Before an except clause's suite is executed, details about the\n" - 'exception are assigned to three variables in the "sys" module:\n' - '"sys.exc_type" receives the object identifying the exception;\n' - '"sys.exc_value" receives the exception\'s parameter;\n' - '"sys.exc_traceback" receives a traceback object (see section The\n' - 'standard type hierarchy) identifying the point in the program where\n' - 'the exception occurred. These details are also available through the\n' - '"sys.exc_info()" function, which returns a tuple "(exc_type,\n' - 'exc_value, exc_traceback)". Use of the corresponding variables is\n' - 'deprecated in favor of this function, since their use is unsafe in a\n' - 'threaded program. As of Python 1.5, the variables are restored to\n' - 'their previous values (before the call) when returning from a ' - 'function\n' - 'that handled an exception.\n' - '\n' - 'The optional "else" clause is executed if and when control flows off\n' - 'the end of the "try" clause. [2] Exceptions in the "else" clause are\n' - 'not handled by the preceding "except" clauses.\n' - '\n' - 'If "finally" is present, it specifies a \'cleanup\' handler. The ' - '"try"\n' - 'clause is executed, including any "except" and "else" clauses. If ' - 'an\n' - 'exception occurs in any of the clauses and is not handled, the\n' - 'exception is temporarily saved. The "finally" clause is executed. ' - 'If\n' - 'there is a saved exception, it is re-raised at the end of the\n' - '"finally" clause. If the "finally" clause raises another exception ' - 'or\n' - 'executes a "return" or "break" statement, the saved exception is\n' - 'discarded:\n' - '\n' - ' >>> def f():\n' - ' ... try:\n' - ' ... 1/0\n' - ' ... finally:\n' - ' ... return 42\n' - ' ...\n' - ' >>> f()\n' - ' 42\n' - '\n' - 'The exception information is not available to the program during\n' - 'execution of the "finally" clause.\n' - '\n' - 'When a "return", "break" or "continue" statement is executed in the\n' - '"try" suite of a "try"..."finally" statement, the "finally" clause ' - 'is\n' - 'also executed \'on the way out.\' A "continue" statement is illegal ' - 'in\n' - 'the "finally" clause. (The reason is a problem with the current\n' - 'implementation --- this restriction may be lifted in the future).\n' - '\n' - 'The return value of a function is determined by the last "return"\n' - 'statement executed. Since the "finally" clause always executes, a\n' - '"return" statement executed in the "finally" clause will always be ' - 'the\n' - 'last one executed:\n' - '\n' - ' >>> def foo():\n' - ' ... try:\n' - " ... return 'try'\n" - ' ... finally:\n' - " ... return 'finally'\n" - ' ...\n' - ' >>> foo()\n' - " 'finally'\n" - '\n' - 'Additional information on exceptions can be found in section\n' - 'Exceptions, and information on using the "raise" statement to ' - 'generate\n' - 'exceptions may be found in section The raise statement.\n', - 'types': '\n' - 'The standard type hierarchy\n' - '***************************\n' - '\n' - 'Below is a list of the types that are built into Python. ' - 'Extension\n' - 'modules (written in C, Java, or other languages, depending on the\n' - 'implementation) can define additional types. Future versions of\n' - 'Python may add types to the type hierarchy (e.g., rational ' - 'numbers,\n' - 'efficiently stored arrays of integers, etc.).\n' - '\n' - 'Some of the type descriptions below contain a paragraph listing\n' - "'special attributes.' These are attributes that provide access to " - 'the\n' - 'implementation and are not intended for general use. Their ' - 'definition\n' - 'may change in the future.\n' - '\n' - 'None\n' - ' This type has a single value. There is a single object with ' - 'this\n' - ' value. This object is accessed through the built-in name "None". ' - 'It\n' - ' is used to signify the absence of a value in many situations, ' - 'e.g.,\n' - " it is returned from functions that don't explicitly return\n" - ' anything. Its truth value is false.\n' - '\n' - 'NotImplemented\n' - ' This type has a single value. There is a single object with ' - 'this\n' - ' value. This object is accessed through the built-in name\n' - ' "NotImplemented". Numeric methods and rich comparison methods ' - 'may\n' - ' return this value if they do not implement the operation for ' - 'the\n' - ' operands provided. (The interpreter will then try the ' - 'reflected\n' - ' operation, or some other fallback, depending on the operator.) ' - 'Its\n' - ' truth value is true.\n' - '\n' - 'Ellipsis\n' - ' This type has a single value. There is a single object with ' - 'this\n' - ' value. This object is accessed through the built-in name\n' - ' "Ellipsis". It is used to indicate the presence of the "..." ' - 'syntax\n' - ' in a slice. Its truth value is true.\n' - '\n' - '"numbers.Number"\n' - ' These are created by numeric literals and returned as results ' - 'by\n' - ' arithmetic operators and arithmetic built-in functions. ' - 'Numeric\n' - ' objects are immutable; once created their value never changes.\n' - ' Python numbers are of course strongly related to mathematical\n' - ' numbers, but subject to the limitations of numerical ' - 'representation\n' - ' in computers.\n' - '\n' - ' Python distinguishes between integers, floating point numbers, ' - 'and\n' - ' complex numbers:\n' - '\n' - ' "numbers.Integral"\n' - ' These represent elements from the mathematical set of ' - 'integers\n' - ' (positive and negative).\n' - '\n' - ' There are three types of integers:\n' - '\n' - ' Plain integers\n' - ' These represent numbers in the range -2147483648 through\n' - ' 2147483647. (The range may be larger on machines with a\n' - ' larger natural word size, but not smaller.) When the ' - 'result\n' - ' of an operation would fall outside this range, the result ' - 'is\n' - ' normally returned as a long integer (in some cases, the\n' - ' exception "OverflowError" is raised instead). For the\n' - ' purpose of shift and mask operations, integers are assumed ' - 'to\n' - " have a binary, 2's complement notation using 32 or more " - 'bits,\n' - ' and hiding no bits from the user (i.e., all 4294967296\n' - ' different bit patterns correspond to different values).\n' - '\n' - ' Long integers\n' - ' These represent numbers in an unlimited range, subject to\n' - ' available (virtual) memory only. For the purpose of ' - 'shift\n' - ' and mask operations, a binary representation is assumed, ' - 'and\n' - " negative numbers are represented in a variant of 2's\n" - ' complement which gives the illusion of an infinite string ' - 'of\n' - ' sign bits extending to the left.\n' - '\n' - ' Booleans\n' - ' These represent the truth values False and True. The two\n' - ' objects representing the values "False" and "True" are ' - 'the\n' - ' only Boolean objects. The Boolean type is a subtype of ' - 'plain\n' - ' integers, and Boolean values behave like the values 0 and ' - '1,\n' - ' respectively, in almost all contexts, the exception being\n' - ' that when converted to a string, the strings ""False"" or\n' - ' ""True"" are returned, respectively.\n' - '\n' - ' The rules for integer representation are intended to give ' - 'the\n' - ' most meaningful interpretation of shift and mask operations\n' - ' involving negative integers and the least surprises when\n' - ' switching between the plain and long integer domains. Any\n' - ' operation, if it yields a result in the plain integer ' - 'domain,\n' - ' will yield the same result in the long integer domain or ' - 'when\n' - ' using mixed operands. The switch between domains is ' - 'transparent\n' - ' to the programmer.\n' - '\n' - ' "numbers.Real" ("float")\n' - ' These represent machine-level double precision floating ' - 'point\n' - ' numbers. You are at the mercy of the underlying machine\n' - ' architecture (and C or Java implementation) for the accepted\n' - ' range and handling of overflow. Python does not support ' - 'single-\n' - ' precision floating point numbers; the savings in processor ' - 'and\n' - ' memory usage that are usually the reason for using these are\n' - ' dwarfed by the overhead of using objects in Python, so there ' - 'is\n' - ' no reason to complicate the language with two kinds of ' - 'floating\n' - ' point numbers.\n' - '\n' - ' "numbers.Complex"\n' - ' These represent complex numbers as a pair of machine-level\n' - ' double precision floating point numbers. The same caveats ' - 'apply\n' - ' as for floating point numbers. The real and imaginary parts ' - 'of a\n' - ' complex number "z" can be retrieved through the read-only\n' - ' attributes "z.real" and "z.imag".\n' - '\n' - 'Sequences\n' - ' These represent finite ordered sets indexed by non-negative\n' - ' numbers. The built-in function "len()" returns the number of ' - 'items\n' - ' of a sequence. When the length of a sequence is *n*, the index ' - 'set\n' - ' contains the numbers 0, 1, ..., *n*-1. Item *i* of sequence *a* ' - 'is\n' - ' selected by "a[i]".\n' - '\n' - ' Sequences also support slicing: "a[i:j]" selects all items with\n' - ' index *k* such that *i* "<=" *k* "<" *j*. When used as an\n' - ' expression, a slice is a sequence of the same type. This ' - 'implies\n' - ' that the index set is renumbered so that it starts at 0.\n' - '\n' - ' Some sequences also support "extended slicing" with a third ' - '"step"\n' - ' parameter: "a[i:j:k]" selects all items of *a* with index *x* ' - 'where\n' - ' "x = i + n*k", *n* ">=" "0" and *i* "<=" *x* "<" *j*.\n' - '\n' - ' Sequences are distinguished according to their mutability:\n' - '\n' - ' Immutable sequences\n' - ' An object of an immutable sequence type cannot change once it ' - 'is\n' - ' created. (If the object contains references to other ' - 'objects,\n' - ' these other objects may be mutable and may be changed; ' - 'however,\n' - ' the collection of objects directly referenced by an ' - 'immutable\n' - ' object cannot change.)\n' - '\n' - ' The following types are immutable sequences:\n' - '\n' - ' Strings\n' - ' The items of a string are characters. There is no ' - 'separate\n' - ' character type; a character is represented by a string of ' - 'one\n' - ' item. Characters represent (at least) 8-bit bytes. The\n' - ' built-in functions "chr()" and "ord()" convert between\n' - ' characters and nonnegative integers representing the byte\n' - ' values. Bytes with the values 0--127 usually represent ' - 'the\n' - ' corresponding ASCII values, but the interpretation of ' - 'values\n' - ' is up to the program. The string data type is also used ' - 'to\n' - ' represent arrays of bytes, e.g., to hold data read from a\n' - ' file.\n' - '\n' - ' (On systems whose native character set is not ASCII, ' - 'strings\n' - ' may use EBCDIC in their internal representation, provided ' - 'the\n' - ' functions "chr()" and "ord()" implement a mapping between\n' - ' ASCII and EBCDIC, and string comparison preserves the ' - 'ASCII\n' - ' order. Or perhaps someone can propose a better rule?)\n' - '\n' - ' Unicode\n' - ' The items of a Unicode object are Unicode code units. A\n' - ' Unicode code unit is represented by a Unicode object of ' - 'one\n' - ' item and can hold either a 16-bit or 32-bit value\n' - ' representing a Unicode ordinal (the maximum value for the\n' - ' ordinal is given in "sys.maxunicode", and depends on how\n' - ' Python is configured at compile time). Surrogate pairs ' - 'may\n' - ' be present in the Unicode object, and will be reported as ' - 'two\n' - ' separate items. The built-in functions "unichr()" and\n' - ' "ord()" convert between code units and nonnegative ' - 'integers\n' - ' representing the Unicode ordinals as defined in the ' - 'Unicode\n' - ' Standard 3.0. Conversion from and to other encodings are\n' - ' possible through the Unicode method "encode()" and the ' - 'built-\n' - ' in function "unicode()".\n' - '\n' - ' Tuples\n' - ' The items of a tuple are arbitrary Python objects. Tuples ' - 'of\n' - ' two or more items are formed by comma-separated lists of\n' - " expressions. A tuple of one item (a 'singleton') can be\n" - ' formed by affixing a comma to an expression (an expression ' - 'by\n' - ' itself does not create a tuple, since parentheses must be\n' - ' usable for grouping of expressions). An empty tuple can ' - 'be\n' - ' formed by an empty pair of parentheses.\n' - '\n' - ' Mutable sequences\n' - ' Mutable sequences can be changed after they are created. ' - 'The\n' - ' subscription and slicing notations can be used as the target ' - 'of\n' - ' assignment and "del" (delete) statements.\n' - '\n' - ' There are currently two intrinsic mutable sequence types:\n' - '\n' - ' Lists\n' - ' The items of a list are arbitrary Python objects. Lists ' - 'are\n' - ' formed by placing a comma-separated list of expressions ' - 'in\n' - ' square brackets. (Note that there are no special cases ' - 'needed\n' - ' to form lists of length 0 or 1.)\n' - '\n' - ' Byte Arrays\n' - ' A bytearray object is a mutable array. They are created ' - 'by\n' - ' the built-in "bytearray()" constructor. Aside from being\n' - ' mutable (and hence unhashable), byte arrays otherwise ' - 'provide\n' - ' the same interface and functionality as immutable bytes\n' - ' objects.\n' - '\n' - ' The extension module "array" provides an additional example ' - 'of a\n' - ' mutable sequence type.\n' - '\n' - 'Set types\n' - ' These represent unordered, finite sets of unique, immutable\n' - ' objects. As such, they cannot be indexed by any subscript. ' - 'However,\n' - ' they can be iterated over, and the built-in function "len()"\n' - ' returns the number of items in a set. Common uses for sets are ' - 'fast\n' - ' membership testing, removing duplicates from a sequence, and\n' - ' computing mathematical operations such as intersection, union,\n' - ' difference, and symmetric difference.\n' - '\n' - ' For set elements, the same immutability rules apply as for\n' - ' dictionary keys. Note that numeric types obey the normal rules ' - 'for\n' - ' numeric comparison: if two numbers compare equal (e.g., "1" and\n' - ' "1.0"), only one of them can be contained in a set.\n' - '\n' - ' There are currently two intrinsic set types:\n' - '\n' - ' Sets\n' - ' These represent a mutable set. They are created by the ' - 'built-in\n' - ' "set()" constructor and can be modified afterwards by ' - 'several\n' - ' methods, such as "add()".\n' - '\n' - ' Frozen sets\n' - ' These represent an immutable set. They are created by the\n' - ' built-in "frozenset()" constructor. As a frozenset is ' - 'immutable\n' - ' and *hashable*, it can be used again as an element of ' - 'another\n' - ' set, or as a dictionary key.\n' - '\n' - 'Mappings\n' - ' These represent finite sets of objects indexed by arbitrary ' - 'index\n' - ' sets. The subscript notation "a[k]" selects the item indexed by ' - '"k"\n' - ' from the mapping "a"; this can be used in expressions and as ' - 'the\n' - ' target of assignments or "del" statements. The built-in ' - 'function\n' - ' "len()" returns the number of items in a mapping.\n' - '\n' - ' There is currently a single intrinsic mapping type:\n' - '\n' - ' Dictionaries\n' - ' These represent finite sets of objects indexed by nearly\n' - ' arbitrary values. The only types of values not acceptable ' - 'as\n' - ' keys are values containing lists or dictionaries or other\n' - ' mutable types that are compared by value rather than by ' - 'object\n' - ' identity, the reason being that the efficient implementation ' - 'of\n' - " dictionaries requires a key's hash value to remain constant.\n" - ' Numeric types used for keys obey the normal rules for ' - 'numeric\n' - ' comparison: if two numbers compare equal (e.g., "1" and ' - '"1.0")\n' - ' then they can be used interchangeably to index the same\n' - ' dictionary entry.\n' - '\n' - ' Dictionaries are mutable; they can be created by the "{...}"\n' - ' notation (see section Dictionary displays).\n' - '\n' - ' The extension modules "dbm", "gdbm", and "bsddb" provide\n' - ' additional examples of mapping types.\n' - '\n' - 'Callable types\n' - ' These are the types to which the function call operation (see\n' - ' section Calls) can be applied:\n' - '\n' - ' User-defined functions\n' - ' A user-defined function object is created by a function\n' - ' definition (see section Function definitions). It should be\n' - ' called with an argument list containing the same number of ' - 'items\n' - " as the function's formal parameter list.\n" - '\n' - ' Special attributes:\n' - '\n' - ' ' - '+-------------------------+---------------------------------+-------------+\n' - ' | Attribute | Meaning ' - '| |\n' - ' ' - '+=========================+=================================+=============+\n' - ' | "__doc__" "func_doc" | The function\'s documentation ' - '| Writable |\n' - ' | | string, or "None" if ' - '| |\n' - ' | | unavailable. ' - '| |\n' - ' ' - '+-------------------------+---------------------------------+-------------+\n' - ' | "__name__" "func_name" | The function\'s name ' - '| Writable |\n' - ' ' - '+-------------------------+---------------------------------+-------------+\n' - ' | "__module__" | The name of the module the | ' - 'Writable |\n' - ' | | function was defined in, or ' - '| |\n' - ' | | "None" if unavailable. ' - '| |\n' - ' ' - '+-------------------------+---------------------------------+-------------+\n' - ' | "__defaults__" | A tuple containing default | ' - 'Writable |\n' - ' | "func_defaults" | argument values for those ' - '| |\n' - ' | | arguments that have defaults, ' - '| |\n' - ' | | or "None" if no arguments have ' - '| |\n' - ' | | a default value. ' - '| |\n' - ' ' - '+-------------------------+---------------------------------+-------------+\n' - ' | "__code__" "func_code" | The code object representing | ' - 'Writable |\n' - ' | | the compiled function body. ' - '| |\n' - ' ' - '+-------------------------+---------------------------------+-------------+\n' - ' | "__globals__" | A reference to the dictionary | ' - 'Read-only |\n' - ' | "func_globals" | that holds the function\'s ' - '| |\n' - ' | | global variables --- the global ' - '| |\n' - ' | | namespace of the module in ' - '| |\n' - ' | | which the function was defined. ' - '| |\n' - ' ' - '+-------------------------+---------------------------------+-------------+\n' - ' | "__dict__" "func_dict" | The namespace supporting | ' - 'Writable |\n' - ' | | arbitrary function attributes. ' - '| |\n' - ' ' - '+-------------------------+---------------------------------+-------------+\n' - ' | "__closure__" | "None" or a tuple of cells that | ' - 'Read-only |\n' - ' | "func_closure" | contain bindings for the ' - '| |\n' - " | | function's free variables. " - '| |\n' - ' ' - '+-------------------------+---------------------------------+-------------+\n' - '\n' - ' Most of the attributes labelled "Writable" check the type of ' - 'the\n' - ' assigned value.\n' - '\n' - ' Changed in version 2.4: "func_name" is now writable.\n' - '\n' - ' Changed in version 2.6: The double-underscore attributes\n' - ' "__closure__", "__code__", "__defaults__", and "__globals__"\n' - ' were introduced as aliases for the corresponding "func_*"\n' - ' attributes for forwards compatibility with Python 3.\n' - '\n' - ' Function objects also support getting and setting arbitrary\n' - ' attributes, which can be used, for example, to attach ' - 'metadata\n' - ' to functions. Regular attribute dot-notation is used to get ' - 'and\n' - ' set such attributes. *Note that the current implementation ' - 'only\n' - ' supports function attributes on user-defined functions. ' - 'Function\n' - ' attributes on built-in functions may be supported in the\n' - ' future.*\n' - '\n' - " Additional information about a function's definition can be\n" - ' retrieved from its code object; see the description of ' - 'internal\n' - ' types below.\n' - '\n' - ' User-defined methods\n' - ' A user-defined method object combines a class, a class ' - 'instance\n' - ' (or "None") and any callable object (normally a user-defined\n' - ' function).\n' - '\n' - ' Special read-only attributes: "im_self" is the class ' - 'instance\n' - ' object, "im_func" is the function object; "im_class" is the\n' - ' class of "im_self" for bound methods or the class that asked ' - 'for\n' - ' the method for unbound methods; "__doc__" is the method\'s\n' - ' documentation (same as "im_func.__doc__"); "__name__" is the\n' - ' method name (same as "im_func.__name__"); "__module__" is ' - 'the\n' - ' name of the module the method was defined in, or "None" if\n' - ' unavailable.\n' - '\n' - ' Changed in version 2.2: "im_self" used to refer to the class\n' - ' that defined the method.\n' - '\n' - ' Changed in version 2.6: For Python 3 forward-compatibility,\n' - ' "im_func" is also available as "__func__", and "im_self" as\n' - ' "__self__".\n' - '\n' - ' Methods also support accessing (but not setting) the ' - 'arbitrary\n' - ' function attributes on the underlying function object.\n' - '\n' - ' User-defined method objects may be created when getting an\n' - ' attribute of a class (perhaps via an instance of that class), ' - 'if\n' - ' that attribute is a user-defined function object, an unbound\n' - ' user-defined method object, or a class method object. When ' - 'the\n' - ' attribute is a user-defined method object, a new method ' - 'object\n' - ' is only created if the class from which it is being retrieved ' - 'is\n' - ' the same as, or a derived class of, the class stored in the\n' - ' original method object; otherwise, the original method object ' - 'is\n' - ' used as it is.\n' - '\n' - ' When a user-defined method object is created by retrieving a\n' - ' user-defined function object from a class, its "im_self"\n' - ' attribute is "None" and the method object is said to be ' - 'unbound.\n' - ' When one is created by retrieving a user-defined function ' - 'object\n' - ' from a class via one of its instances, its "im_self" ' - 'attribute\n' - ' is the instance, and the method object is said to be bound. ' - 'In\n' - ' either case, the new method\'s "im_class" attribute is the ' - 'class\n' - ' from which the retrieval takes place, and its "im_func"\n' - ' attribute is the original function object.\n' - '\n' - ' When a user-defined method object is created by retrieving\n' - ' another method object from a class or instance, the behaviour ' - 'is\n' - ' the same as for a function object, except that the "im_func"\n' - ' attribute of the new instance is not the original method ' - 'object\n' - ' but its "im_func" attribute.\n' - '\n' - ' When a user-defined method object is created by retrieving a\n' - ' class method object from a class or instance, its "im_self"\n' - ' attribute is the class itself, and its "im_func" attribute ' - 'is\n' - ' the function object underlying the class method.\n' - '\n' - ' When an unbound user-defined method object is called, the\n' - ' underlying function ("im_func") is called, with the ' - 'restriction\n' - ' that the first argument must be an instance of the proper ' - 'class\n' - ' ("im_class") or of a derived class thereof.\n' - '\n' - ' When a bound user-defined method object is called, the\n' - ' underlying function ("im_func") is called, inserting the ' - 'class\n' - ' instance ("im_self") in front of the argument list. For\n' - ' instance, when "C" is a class which contains a definition for ' - 'a\n' - ' function "f()", and "x" is an instance of "C", calling ' - '"x.f(1)"\n' - ' is equivalent to calling "C.f(x, 1)".\n' - '\n' - ' When a user-defined method object is derived from a class ' - 'method\n' - ' object, the "class instance" stored in "im_self" will ' - 'actually\n' - ' be the class itself, so that calling either "x.f(1)" or ' - '"C.f(1)"\n' - ' is equivalent to calling "f(C,1)" where "f" is the ' - 'underlying\n' - ' function.\n' - '\n' - ' Note that the transformation from function object to (unbound ' - 'or\n' - ' bound) method object happens each time the attribute is\n' - ' retrieved from the class or instance. In some cases, a ' - 'fruitful\n' - ' optimization is to assign the attribute to a local variable ' - 'and\n' - ' call that local variable. Also notice that this ' - 'transformation\n' - ' only happens for user-defined functions; other callable ' - 'objects\n' - ' (and all non-callable objects) are retrieved without\n' - ' transformation. It is also important to note that ' - 'user-defined\n' - ' functions which are attributes of a class instance are not\n' - ' converted to bound methods; this *only* happens when the\n' - ' function is an attribute of the class.\n' - '\n' - ' Generator functions\n' - ' A function or method which uses the "yield" statement (see\n' - ' section The yield statement) is called a *generator ' - 'function*.\n' - ' Such a function, when called, always returns an iterator ' - 'object\n' - ' which can be used to execute the body of the function: ' - 'calling\n' - ' the iterator\'s "next()" method will cause the function to\n' - ' execute until it provides a value using the "yield" ' - 'statement.\n' - ' When the function executes a "return" statement or falls off ' - 'the\n' - ' end, a "StopIteration" exception is raised and the iterator ' - 'will\n' - ' have reached the end of the set of values to be returned.\n' - '\n' - ' Built-in functions\n' - ' A built-in function object is a wrapper around a C function.\n' - ' Examples of built-in functions are "len()" and "math.sin()"\n' - ' ("math" is a standard built-in module). The number and type ' - 'of\n' - ' the arguments are determined by the C function. Special ' - 'read-\n' - ' only attributes: "__doc__" is the function\'s documentation\n' - ' string, or "None" if unavailable; "__name__" is the ' - "function's\n" - ' name; "__self__" is set to "None" (but see the next item);\n' - ' "__module__" is the name of the module the function was ' - 'defined\n' - ' in or "None" if unavailable.\n' - '\n' - ' Built-in methods\n' - ' This is really a different disguise of a built-in function, ' - 'this\n' - ' time containing an object passed to the C function as an\n' - ' implicit extra argument. An example of a built-in method is\n' - ' "alist.append()", assuming *alist* is a list object. In this\n' - ' case, the special read-only attribute "__self__" is set to ' - 'the\n' - ' object denoted by *alist*.\n' - '\n' - ' Class Types\n' - ' Class types, or "new-style classes," are callable. These\n' - ' objects normally act as factories for new instances of\n' - ' themselves, but variations are possible for class types that\n' - ' override "__new__()". The arguments of the call are passed ' - 'to\n' - ' "__new__()" and, in the typical case, to "__init__()" to\n' - ' initialize the new instance.\n' - '\n' - ' Classic Classes\n' - ' Class objects are described below. When a class object is\n' - ' called, a new class instance (also described below) is ' - 'created\n' - " and returned. This implies a call to the class's " - '"__init__()"\n' - ' method if it has one. Any arguments are passed on to the\n' - ' "__init__()" method. If there is no "__init__()" method, ' - 'the\n' - ' class must be called without arguments.\n' - '\n' - ' Class instances\n' - ' Class instances are described below. Class instances are\n' - ' callable only when the class has a "__call__()" method;\n' - ' "x(arguments)" is a shorthand for "x.__call__(arguments)".\n' - '\n' - 'Modules\n' - ' Modules are imported by the "import" statement (see section The\n' - ' import statement). A module object has a namespace implemented ' - 'by a\n' - ' dictionary object (this is the dictionary referenced by the\n' - ' func_globals attribute of functions defined in the module).\n' - ' Attribute references are translated to lookups in this ' - 'dictionary,\n' - ' e.g., "m.x" is equivalent to "m.__dict__["x"]". A module object\n' - ' does not contain the code object used to initialize the module\n' - " (since it isn't needed once the initialization is done).\n" - '\n' - " Attribute assignment updates the module's namespace dictionary,\n" - ' e.g., "m.x = 1" is equivalent to "m.__dict__["x"] = 1".\n' - '\n' - ' Special read-only attribute: "__dict__" is the module\'s ' - 'namespace\n' - ' as a dictionary object.\n' - '\n' - ' **CPython implementation detail:** Because of the way CPython\n' - ' clears module dictionaries, the module dictionary will be ' - 'cleared\n' - ' when the module falls out of scope even if the dictionary still ' - 'has\n' - ' live references. To avoid this, copy the dictionary or keep ' - 'the\n' - ' module around while using its dictionary directly.\n' - '\n' - ' Predefined (writable) attributes: "__name__" is the module\'s ' - 'name;\n' - ' "__doc__" is the module\'s documentation string, or "None" if\n' - ' unavailable; "__file__" is the pathname of the file from which ' - 'the\n' - ' module was loaded, if it was loaded from a file. The "__file__"\n' - ' attribute is not present for C modules that are statically ' - 'linked\n' - ' into the interpreter; for extension modules loaded dynamically ' - 'from\n' - ' a shared library, it is the pathname of the shared library ' - 'file.\n' - '\n' - 'Classes\n' - ' Both class types (new-style classes) and class objects (old-\n' - ' style/classic classes) are typically created by class ' - 'definitions\n' - ' (see section Class definitions). A class has a namespace\n' - ' implemented by a dictionary object. Class attribute references ' - 'are\n' - ' translated to lookups in this dictionary, e.g., "C.x" is ' - 'translated\n' - ' to "C.__dict__["x"]" (although for new-style classes in ' - 'particular\n' - ' there are a number of hooks which allow for other means of ' - 'locating\n' - ' attributes). When the attribute name is not found there, the\n' - ' attribute search continues in the base classes. For old-style\n' - ' classes, the search is depth-first, left-to-right in the order ' - 'of\n' - ' occurrence in the base class list. New-style classes use the ' - 'more\n' - ' complex C3 method resolution order which behaves correctly even ' - 'in\n' - " the presence of 'diamond' inheritance structures where there " - 'are\n' - ' multiple inheritance paths leading back to a common ancestor.\n' - ' Additional details on the C3 MRO used by new-style classes can ' - 'be\n' - ' found in the documentation accompanying the 2.3 release at\n' - ' https://www.python.org/download/releases/2.3/mro/.\n' - '\n' - ' When a class attribute reference (for class "C", say) would ' - 'yield a\n' - ' user-defined function object or an unbound user-defined method\n' - ' object whose associated class is either "C" or one of its base\n' - ' classes, it is transformed into an unbound user-defined method\n' - ' object whose "im_class" attribute is "C". When it would yield a\n' - ' class method object, it is transformed into a bound ' - 'user-defined\n' - ' method object whose "im_self" attribute is "C". When it would\n' - ' yield a static method object, it is transformed into the object\n' - ' wrapped by the static method object. See section Implementing\n' - ' Descriptors for another way in which attributes retrieved from ' - 'a\n' - ' class may differ from those actually contained in its ' - '"__dict__"\n' - ' (note that only new-style classes support descriptors).\n' - '\n' - " Class attribute assignments update the class's dictionary, " - 'never\n' - ' the dictionary of a base class.\n' - '\n' - ' A class object can be called (see above) to yield a class ' - 'instance\n' - ' (see below).\n' - '\n' - ' Special attributes: "__name__" is the class name; "__module__" ' - 'is\n' - ' the module name in which the class was defined; "__dict__" is ' - 'the\n' - ' dictionary containing the class\'s namespace; "__bases__" is a ' - 'tuple\n' - ' (possibly empty or a singleton) containing the base classes, in ' - 'the\n' - ' order of their occurrence in the base class list; "__doc__" is ' - 'the\n' - ' class\'s documentation string, or "None" if undefined.\n' - '\n' - 'Class instances\n' - ' A class instance is created by calling a class object (see ' - 'above).\n' - ' A class instance has a namespace implemented as a dictionary ' - 'which\n' - ' is the first place in which attribute references are searched.\n' - " When an attribute is not found there, and the instance's class " - 'has\n' - ' an attribute by that name, the search continues with the class\n' - ' attributes. If a class attribute is found that is a ' - 'user-defined\n' - ' function object or an unbound user-defined method object whose\n' - ' associated class is the class (call it "C") of the instance for\n' - ' which the attribute reference was initiated or one of its bases, ' - 'it\n' - ' is transformed into a bound user-defined method object whose\n' - ' "im_class" attribute is "C" and whose "im_self" attribute is ' - 'the\n' - ' instance. Static method and class method objects are also\n' - ' transformed, as if they had been retrieved from class "C"; see\n' - ' above under "Classes". See section Implementing Descriptors for\n' - ' another way in which attributes of a class retrieved via its\n' - ' instances may differ from the objects actually stored in the\n' - ' class\'s "__dict__". If no class attribute is found, and the\n' - ' object\'s class has a "__getattr__()" method, that is called to\n' - ' satisfy the lookup.\n' - '\n' - " Attribute assignments and deletions update the instance's\n" - " dictionary, never a class's dictionary. If the class has a\n" - ' "__setattr__()" or "__delattr__()" method, this is called ' - 'instead\n' - ' of updating the instance dictionary directly.\n' - '\n' - ' Class instances can pretend to be numbers, sequences, or ' - 'mappings\n' - ' if they have methods with certain special names. See section\n' - ' Special method names.\n' - '\n' - ' Special attributes: "__dict__" is the attribute dictionary;\n' - ' "__class__" is the instance\'s class.\n' - '\n' - 'Files\n' - ' A file object represents an open file. File objects are created ' - 'by\n' - ' the "open()" built-in function, and also by "os.popen()",\n' - ' "os.fdopen()", and the "makefile()" method of socket objects ' - '(and\n' - ' perhaps by other functions or methods provided by extension\n' - ' modules). The objects "sys.stdin", "sys.stdout" and ' - '"sys.stderr"\n' - ' are initialized to file objects corresponding to the ' - "interpreter's\n" - ' standard input, output and error streams. See File Objects for\n' - ' complete documentation of file objects.\n' - '\n' - 'Internal types\n' - ' A few types used internally by the interpreter are exposed to ' - 'the\n' - ' user. Their definitions may change with future versions of the\n' - ' interpreter, but they are mentioned here for completeness.\n' - '\n' - ' Code objects\n' - ' Code objects represent *byte-compiled* executable Python ' - 'code,\n' - ' or *bytecode*. The difference between a code object and a\n' - ' function object is that the function object contains an ' - 'explicit\n' - " reference to the function's globals (the module in which it " - 'was\n' - ' defined), while a code object contains no context; also the\n' - ' default argument values are stored in the function object, ' - 'not\n' - ' in the code object (because they represent values calculated ' - 'at\n' - ' run-time). Unlike function objects, code objects are ' - 'immutable\n' - ' and contain no references (directly or indirectly) to ' - 'mutable\n' - ' objects.\n' - '\n' - ' Special read-only attributes: "co_name" gives the function ' - 'name;\n' - ' "co_argcount" is the number of positional arguments ' - '(including\n' - ' arguments with default values); "co_nlocals" is the number ' - 'of\n' - ' local variables used by the function (including arguments);\n' - ' "co_varnames" is a tuple containing the names of the local\n' - ' variables (starting with the argument names); "co_cellvars" ' - 'is a\n' - ' tuple containing the names of local variables that are\n' - ' referenced by nested functions; "co_freevars" is a tuple\n' - ' containing the names of free variables; "co_code" is a ' - 'string\n' - ' representing the sequence of bytecode instructions; ' - '"co_consts"\n' - ' is a tuple containing the literals used by the bytecode;\n' - ' "co_names" is a tuple containing the names used by the ' - 'bytecode;\n' - ' "co_filename" is the filename from which the code was ' - 'compiled;\n' - ' "co_firstlineno" is the first line number of the function;\n' - ' "co_lnotab" is a string encoding the mapping from bytecode\n' - ' offsets to line numbers (for details see the source code of ' - 'the\n' - ' interpreter); "co_stacksize" is the required stack size\n' - ' (including local variables); "co_flags" is an integer ' - 'encoding a\n' - ' number of flags for the interpreter.\n' - '\n' - ' The following flag bits are defined for "co_flags": bit ' - '"0x04"\n' - ' is set if the function uses the "*arguments" syntax to accept ' - 'an\n' - ' arbitrary number of positional arguments; bit "0x08" is set ' - 'if\n' - ' the function uses the "**keywords" syntax to accept ' - 'arbitrary\n' - ' keyword arguments; bit "0x20" is set if the function is a\n' - ' generator.\n' - '\n' - ' Future feature declarations ("from __future__ import ' - 'division")\n' - ' also use bits in "co_flags" to indicate whether a code ' - 'object\n' - ' was compiled with a particular feature enabled: bit "0x2000" ' - 'is\n' - ' set if the function was compiled with future division ' - 'enabled;\n' - ' bits "0x10" and "0x1000" were used in earlier versions of\n' - ' Python.\n' - '\n' - ' Other bits in "co_flags" are reserved for internal use.\n' - '\n' - ' If a code object represents a function, the first item in\n' - ' "co_consts" is the documentation string of the function, or\n' - ' "None" if undefined.\n' - '\n' - ' Frame objects\n' - ' Frame objects represent execution frames. They may occur in\n' - ' traceback objects (see below).\n' - '\n' - ' Special read-only attributes: "f_back" is to the previous ' - 'stack\n' - ' frame (towards the caller), or "None" if this is the bottom\n' - ' stack frame; "f_code" is the code object being executed in ' - 'this\n' - ' frame; "f_locals" is the dictionary used to look up local\n' - ' variables; "f_globals" is used for global variables;\n' - ' "f_builtins" is used for built-in (intrinsic) names;\n' - ' "f_restricted" is a flag indicating whether the function is\n' - ' executing in restricted execution mode; "f_lasti" gives the\n' - ' precise instruction (this is an index into the bytecode ' - 'string\n' - ' of the code object).\n' - '\n' - ' Special writable attributes: "f_trace", if not "None", is a\n' - ' function called at the start of each source code line (this ' - 'is\n' - ' used by the debugger); "f_exc_type", "f_exc_value",\n' - ' "f_exc_traceback" represent the last exception raised in the\n' - ' parent frame provided another exception was ever raised in ' - 'the\n' - ' current frame (in all other cases they are "None"); ' - '"f_lineno"\n' - ' is the current line number of the frame --- writing to this ' - 'from\n' - ' within a trace function jumps to the given line (only for ' - 'the\n' - ' bottom-most frame). A debugger can implement a Jump command\n' - ' (aka Set Next Statement) by writing to f_lineno.\n' - '\n' - ' Traceback objects\n' - ' Traceback objects represent a stack trace of an exception. ' - 'A\n' - ' traceback object is created when an exception occurs. When ' - 'the\n' - ' search for an exception handler unwinds the execution stack, ' - 'at\n' - ' each unwound level a traceback object is inserted in front ' - 'of\n' - ' the current traceback. When an exception handler is ' - 'entered,\n' - ' the stack trace is made available to the program. (See ' - 'section\n' - ' The try statement.) It is accessible as "sys.exc_traceback", ' - 'and\n' - ' also as the third item of the tuple returned by\n' - ' "sys.exc_info()". The latter is the preferred interface, ' - 'since\n' - ' it works correctly when the program is using multiple ' - 'threads.\n' - ' When the program contains no suitable handler, the stack ' - 'trace\n' - ' is written (nicely formatted) to the standard error stream; ' - 'if\n' - ' the interpreter is interactive, it is also made available to ' - 'the\n' - ' user as "sys.last_traceback".\n' - '\n' - ' Special read-only attributes: "tb_next" is the next level in ' - 'the\n' - ' stack trace (towards the frame where the exception occurred), ' - 'or\n' - ' "None" if there is no next level; "tb_frame" points to the\n' - ' execution frame of the current level; "tb_lineno" gives the ' - 'line\n' - ' number where the exception occurred; "tb_lasti" indicates ' - 'the\n' - ' precise instruction. The line number and last instruction ' - 'in\n' - ' the traceback may differ from the line number of its frame\n' - ' object if the exception occurred in a "try" statement with ' - 'no\n' - ' matching except clause or with a finally clause.\n' - '\n' - ' Slice objects\n' - ' Slice objects are used to represent slices when *extended ' - 'slice\n' - ' syntax* is used. This is a slice using two colons, or ' - 'multiple\n' - ' slices or ellipses separated by commas, e.g., "a[i:j:step]",\n' - ' "a[i:j, k:l]", or "a[..., i:j]". They are also created by ' - 'the\n' - ' built-in "slice()" function.\n' - '\n' - ' Special read-only attributes: "start" is the lower bound; ' - '"stop"\n' - ' is the upper bound; "step" is the step value; each is "None" ' - 'if\n' - ' omitted. These attributes can have any type.\n' - '\n' - ' Slice objects support one method:\n' - '\n' - ' slice.indices(self, length)\n' - '\n' - ' This method takes a single integer argument *length* and\n' - ' computes information about the extended slice that the ' - 'slice\n' - ' object would describe if applied to a sequence of ' - '*length*\n' - ' items. It returns a tuple of three integers; ' - 'respectively\n' - ' these are the *start* and *stop* indices and the *step* ' - 'or\n' - ' stride length of the slice. Missing or out-of-bounds ' - 'indices\n' - ' are handled in a manner consistent with regular slices.\n' - '\n' - ' New in version 2.3.\n' - '\n' - ' Static method objects\n' - ' Static method objects provide a way of defeating the\n' - ' transformation of function objects to method objects ' - 'described\n' - ' above. A static method object is a wrapper around any other\n' - ' object, usually a user-defined method object. When a static\n' - ' method object is retrieved from a class or a class instance, ' - 'the\n' - ' object actually returned is the wrapped object, which is not\n' - ' subject to any further transformation. Static method objects ' - 'are\n' - ' not themselves callable, although the objects they wrap ' - 'usually\n' - ' are. Static method objects are created by the built-in\n' - ' "staticmethod()" constructor.\n' - '\n' - ' Class method objects\n' - ' A class method object, like a static method object, is a ' - 'wrapper\n' - ' around another object that alters the way in which that ' - 'object\n' - ' is retrieved from classes and class instances. The behaviour ' - 'of\n' - ' class method objects upon such retrieval is described above,\n' - ' under "User-defined methods". Class method objects are ' - 'created\n' - ' by the built-in "classmethod()" constructor.\n', - 'typesfunctions': '\n' - 'Functions\n' - '*********\n' - '\n' - 'Function objects are created by function definitions. The ' - 'only\n' - 'operation on a function object is to call it: ' - '"func(argument-list)".\n' - '\n' - 'There are really two flavors of function objects: built-in ' - 'functions\n' - 'and user-defined functions. Both support the same ' - 'operation (to call\n' - 'the function), but the implementation is different, hence ' - 'the\n' - 'different object types.\n' - '\n' - 'See Function definitions for more information.\n', - 'typesmapping': '\n' - 'Mapping Types --- "dict"\n' - '************************\n' - '\n' - 'A *mapping* object maps *hashable* values to arbitrary ' - 'objects.\n' - 'Mappings are mutable objects. There is currently only one ' - 'standard\n' - 'mapping type, the *dictionary*. (For other containers see ' - 'the built\n' - 'in "list", "set", and "tuple" classes, and the "collections" ' - 'module.)\n' - '\n' - "A dictionary's keys are *almost* arbitrary values. Values " - 'that are\n' - 'not *hashable*, that is, values containing lists, ' - 'dictionaries or\n' - 'other mutable types (that are compared by value rather than ' - 'by object\n' - 'identity) may not be used as keys. Numeric types used for ' - 'keys obey\n' - 'the normal rules for numeric comparison: if two numbers ' - 'compare equal\n' - '(such as "1" and "1.0") then they can be used ' - 'interchangeably to index\n' - 'the same dictionary entry. (Note however, that since ' - 'computers store\n' - 'floating-point numbers as approximations it is usually ' - 'unwise to use\n' - 'them as dictionary keys.)\n' - '\n' - 'Dictionaries can be created by placing a comma-separated ' - 'list of "key:\n' - 'value" pairs within braces, for example: "{\'jack\': 4098, ' - "'sjoerd':\n" - '4127}" or "{4098: \'jack\', 4127: \'sjoerd\'}", or by the ' - '"dict"\n' - 'constructor.\n' - '\n' - 'class dict(**kwarg)\n' - 'class dict(mapping, **kwarg)\n' - 'class dict(iterable, **kwarg)\n' - '\n' - ' Return a new dictionary initialized from an optional ' - 'positional\n' - ' argument and a possibly empty set of keyword arguments.\n' - '\n' - ' If no positional argument is given, an empty dictionary ' - 'is created.\n' - ' If a positional argument is given and it is a mapping ' - 'object, a\n' - ' dictionary is created with the same key-value pairs as ' - 'the mapping\n' - ' object. Otherwise, the positional argument must be an ' - '*iterable*\n' - ' object. Each item in the iterable must itself be an ' - 'iterable with\n' - ' exactly two objects. The first object of each item ' - 'becomes a key\n' - ' in the new dictionary, and the second object the ' - 'corresponding\n' - ' value. If a key occurs more than once, the last value ' - 'for that key\n' - ' becomes the corresponding value in the new dictionary.\n' - '\n' - ' If keyword arguments are given, the keyword arguments and ' - 'their\n' - ' values are added to the dictionary created from the ' - 'positional\n' - ' argument. If a key being added is already present, the ' - 'value from\n' - ' the keyword argument replaces the value from the ' - 'positional\n' - ' argument.\n' - '\n' - ' To illustrate, the following examples all return a ' - 'dictionary equal\n' - ' to "{"one": 1, "two": 2, "three": 3}":\n' - '\n' - ' >>> a = dict(one=1, two=2, three=3)\n' - " >>> b = {'one': 1, 'two': 2, 'three': 3}\n" - " >>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))\n" - " >>> d = dict([('two', 2), ('one', 1), ('three', 3)])\n" - " >>> e = dict({'three': 3, 'one': 1, 'two': 2})\n" - ' >>> a == b == c == d == e\n' - ' True\n' - '\n' - ' Providing keyword arguments as in the first example only ' - 'works for\n' - ' keys that are valid Python identifiers. Otherwise, any ' - 'valid keys\n' - ' can be used.\n' - '\n' - ' New in version 2.2.\n' - '\n' - ' Changed in version 2.3: Support for building a dictionary ' - 'from\n' - ' keyword arguments added.\n' - '\n' - ' These are the operations that dictionaries support (and ' - 'therefore,\n' - ' custom mapping types should support too):\n' - '\n' - ' len(d)\n' - '\n' - ' Return the number of items in the dictionary *d*.\n' - '\n' - ' d[key]\n' - '\n' - ' Return the item of *d* with key *key*. Raises a ' - '"KeyError" if\n' - ' *key* is not in the map.\n' - '\n' - ' If a subclass of dict defines a method "__missing__()" ' - 'and *key*\n' - ' is not present, the "d[key]" operation calls that ' - 'method with\n' - ' the key *key* as argument. The "d[key]" operation ' - 'then returns\n' - ' or raises whatever is returned or raised by the\n' - ' "__missing__(key)" call. No other operations or ' - 'methods invoke\n' - ' "__missing__()". If "__missing__()" is not defined, ' - '"KeyError"\n' - ' is raised. "__missing__()" must be a method; it cannot ' - 'be an\n' - ' instance variable:\n' - '\n' - ' >>> class Counter(dict):\n' - ' ... def __missing__(self, key):\n' - ' ... return 0\n' - ' >>> c = Counter()\n' - " >>> c['red']\n" - ' 0\n' - " >>> c['red'] += 1\n" - " >>> c['red']\n" - ' 1\n' - '\n' - ' The example above shows part of the implementation of\n' - ' "collections.Counter". A different "__missing__" ' - 'method is used\n' - ' by "collections.defaultdict".\n' - '\n' - ' New in version 2.5: Recognition of __missing__ methods ' - 'of dict\n' - ' subclasses.\n' - '\n' - ' d[key] = value\n' - '\n' - ' Set "d[key]" to *value*.\n' - '\n' - ' del d[key]\n' - '\n' - ' Remove "d[key]" from *d*. Raises a "KeyError" if ' - '*key* is not\n' - ' in the map.\n' - '\n' - ' key in d\n' - '\n' - ' Return "True" if *d* has a key *key*, else "False".\n' - '\n' - ' New in version 2.2.\n' - '\n' - ' key not in d\n' - '\n' - ' Equivalent to "not key in d".\n' - '\n' - ' New in version 2.2.\n' - '\n' - ' iter(d)\n' - '\n' - ' Return an iterator over the keys of the dictionary. ' - 'This is a\n' - ' shortcut for "iterkeys()".\n' - '\n' - ' clear()\n' - '\n' - ' Remove all items from the dictionary.\n' - '\n' - ' copy()\n' - '\n' - ' Return a shallow copy of the dictionary.\n' - '\n' - ' fromkeys(seq[, value])\n' - '\n' - ' Create a new dictionary with keys from *seq* and ' - 'values set to\n' - ' *value*.\n' - '\n' - ' "fromkeys()" is a class method that returns a new ' - 'dictionary.\n' - ' *value* defaults to "None".\n' - '\n' - ' New in version 2.3.\n' - '\n' - ' get(key[, default])\n' - '\n' - ' Return the value for *key* if *key* is in the ' - 'dictionary, else\n' - ' *default*. If *default* is not given, it defaults to ' - '"None", so\n' - ' that this method never raises a "KeyError".\n' - '\n' - ' has_key(key)\n' - '\n' - ' Test for the presence of *key* in the dictionary. ' - '"has_key()"\n' - ' is deprecated in favor of "key in d".\n' - '\n' - ' items()\n' - '\n' - ' Return a copy of the dictionary\'s list of "(key, ' - 'value)" pairs.\n' - '\n' - ' **CPython implementation detail:** Keys and values are ' - 'listed in\n' - ' an arbitrary order which is non-random, varies across ' - 'Python\n' - " implementations, and depends on the dictionary's " - 'history of\n' - ' insertions and deletions.\n' - '\n' - ' If "items()", "keys()", "values()", "iteritems()", ' - '"iterkeys()",\n' - ' and "itervalues()" are called with no intervening ' - 'modifications\n' - ' to the dictionary, the lists will directly ' - 'correspond. This\n' - ' allows the creation of "(value, key)" pairs using ' - '"zip()":\n' - ' "pairs = zip(d.values(), d.keys())". The same ' - 'relationship\n' - ' holds for the "iterkeys()" and "itervalues()" methods: ' - '"pairs =\n' - ' zip(d.itervalues(), d.iterkeys())" provides the same ' - 'value for\n' - ' "pairs". Another way to create the same list is "pairs ' - '= [(v, k)\n' - ' for (k, v) in d.iteritems()]".\n' - '\n' - ' iteritems()\n' - '\n' - ' Return an iterator over the dictionary\'s "(key, ' - 'value)" pairs.\n' - ' See the note for "dict.items()".\n' - '\n' - ' Using "iteritems()" while adding or deleting entries ' - 'in the\n' - ' dictionary may raise a "RuntimeError" or fail to ' - 'iterate over\n' - ' all entries.\n' - '\n' - ' New in version 2.2.\n' - '\n' - ' iterkeys()\n' - '\n' - " Return an iterator over the dictionary's keys. See " - 'the note for\n' - ' "dict.items()".\n' - '\n' - ' Using "iterkeys()" while adding or deleting entries in ' - 'the\n' - ' dictionary may raise a "RuntimeError" or fail to ' - 'iterate over\n' - ' all entries.\n' - '\n' - ' New in version 2.2.\n' - '\n' - ' itervalues()\n' - '\n' - " Return an iterator over the dictionary's values. See " - 'the note\n' - ' for "dict.items()".\n' - '\n' - ' Using "itervalues()" while adding or deleting entries ' - 'in the\n' - ' dictionary may raise a "RuntimeError" or fail to ' - 'iterate over\n' - ' all entries.\n' - '\n' - ' New in version 2.2.\n' - '\n' - ' keys()\n' - '\n' - " Return a copy of the dictionary's list of keys. See " - 'the note\n' - ' for "dict.items()".\n' - '\n' - ' pop(key[, default])\n' - '\n' - ' If *key* is in the dictionary, remove it and return ' - 'its value,\n' - ' else return *default*. If *default* is not given and ' - '*key* is\n' - ' not in the dictionary, a "KeyError" is raised.\n' - '\n' - ' New in version 2.3.\n' - '\n' - ' popitem()\n' - '\n' - ' Remove and return an arbitrary "(key, value)" pair ' - 'from the\n' - ' dictionary.\n' - '\n' - ' "popitem()" is useful to destructively iterate over a\n' - ' dictionary, as often used in set algorithms. If the ' - 'dictionary\n' - ' is empty, calling "popitem()" raises a "KeyError".\n' - '\n' - ' setdefault(key[, default])\n' - '\n' - ' If *key* is in the dictionary, return its value. If ' - 'not, insert\n' - ' *key* with a value of *default* and return *default*. ' - '*default*\n' - ' defaults to "None".\n' - '\n' - ' update([other])\n' - '\n' - ' Update the dictionary with the key/value pairs from ' - '*other*,\n' - ' overwriting existing keys. Return "None".\n' - '\n' - ' "update()" accepts either another dictionary object or ' - 'an\n' - ' iterable of key/value pairs (as tuples or other ' - 'iterables of\n' - ' length two). If keyword arguments are specified, the ' - 'dictionary\n' - ' is then updated with those key/value pairs: ' - '"d.update(red=1,\n' - ' blue=2)".\n' - '\n' - ' Changed in version 2.4: Allowed the argument to be an ' - 'iterable\n' - ' of key/value pairs and allowed keyword arguments.\n' - '\n' - ' values()\n' - '\n' - " Return a copy of the dictionary's list of values. See " - 'the note\n' - ' for "dict.items()".\n' - '\n' - ' viewitems()\n' - '\n' - ' Return a new view of the dictionary\'s items ("(key, ' - 'value)"\n' - ' pairs). See below for documentation of view objects.\n' - '\n' - ' New in version 2.7.\n' - '\n' - ' viewkeys()\n' - '\n' - " Return a new view of the dictionary's keys. See below " - 'for\n' - ' documentation of view objects.\n' - '\n' - ' New in version 2.7.\n' - '\n' - ' viewvalues()\n' - '\n' - " Return a new view of the dictionary's values. See " - 'below for\n' - ' documentation of view objects.\n' - '\n' - ' New in version 2.7.\n' - '\n' - ' Dictionaries compare equal if and only if they have the ' - 'same "(key,\n' - ' value)" pairs.\n' - '\n' - '\n' - 'Dictionary view objects\n' - '=======================\n' - '\n' - 'The objects returned by "dict.viewkeys()", ' - '"dict.viewvalues()" and\n' - '"dict.viewitems()" are *view objects*. They provide a ' - 'dynamic view on\n' - "the dictionary's entries, which means that when the " - 'dictionary\n' - 'changes, the view reflects these changes.\n' - '\n' - 'Dictionary views can be iterated over to yield their ' - 'respective data,\n' - 'and support membership tests:\n' - '\n' - 'len(dictview)\n' - '\n' - ' Return the number of entries in the dictionary.\n' - '\n' - 'iter(dictview)\n' - '\n' - ' Return an iterator over the keys, values or items ' - '(represented as\n' - ' tuples of "(key, value)") in the dictionary.\n' - '\n' - ' Keys and values are iterated over in an arbitrary order ' - 'which is\n' - ' non-random, varies across Python implementations, and ' - 'depends on\n' - " the dictionary's history of insertions and deletions. If " - 'keys,\n' - ' values and items views are iterated over with no ' - 'intervening\n' - ' modifications to the dictionary, the order of items will ' - 'directly\n' - ' correspond. This allows the creation of "(value, key)" ' - 'pairs using\n' - ' "zip()": "pairs = zip(d.values(), d.keys())". Another ' - 'way to\n' - ' create the same list is "pairs = [(v, k) for (k, v) in ' - 'd.items()]".\n' - '\n' - ' Iterating views while adding or deleting entries in the ' - 'dictionary\n' - ' may raise a "RuntimeError" or fail to iterate over all ' - 'entries.\n' - '\n' - 'x in dictview\n' - '\n' - ' Return "True" if *x* is in the underlying dictionary\'s ' - 'keys, values\n' - ' or items (in the latter case, *x* should be a "(key, ' - 'value)"\n' - ' tuple).\n' - '\n' - 'Keys views are set-like since their entries are unique and ' - 'hashable.\n' - 'If all values are hashable, so that (key, value) pairs are ' - 'unique and\n' - 'hashable, then the items view is also set-like. (Values ' - 'views are not\n' - 'treated as set-like since the entries are generally not ' - 'unique.) Then\n' - 'these set operations are available ("other" refers either to ' - 'another\n' - 'view or a set):\n' - '\n' - 'dictview & other\n' - '\n' - ' Return the intersection of the dictview and the other ' - 'object as a\n' - ' new set.\n' - '\n' - 'dictview | other\n' - '\n' - ' Return the union of the dictview and the other object as ' - 'a new set.\n' - '\n' - 'dictview - other\n' - '\n' - ' Return the difference between the dictview and the other ' - 'object\n' - " (all elements in *dictview* that aren't in *other*) as a " - 'new set.\n' - '\n' - 'dictview ^ other\n' - '\n' - ' Return the symmetric difference (all elements either in ' - '*dictview*\n' - ' or *other*, but not in both) of the dictview and the ' - 'other object\n' - ' as a new set.\n' - '\n' - 'An example of dictionary view usage:\n' - '\n' - " >>> dishes = {'eggs': 2, 'sausage': 1, 'bacon': 1, " - "'spam': 500}\n" - ' >>> keys = dishes.viewkeys()\n' - ' >>> values = dishes.viewvalues()\n' - '\n' - ' >>> # iteration\n' - ' >>> n = 0\n' - ' >>> for val in values:\n' - ' ... n += val\n' - ' >>> print(n)\n' - ' 504\n' - '\n' - ' >>> # keys and values are iterated over in the same ' - 'order\n' - ' >>> list(keys)\n' - " ['eggs', 'bacon', 'sausage', 'spam']\n" - ' >>> list(values)\n' - ' [2, 1, 1, 500]\n' - '\n' - ' >>> # view objects are dynamic and reflect dict changes\n' - " >>> del dishes['eggs']\n" - " >>> del dishes['sausage']\n" - ' >>> list(keys)\n' - " ['spam', 'bacon']\n" - '\n' - ' >>> # set operations\n' - " >>> keys & {'eggs', 'bacon', 'salad'}\n" - " {'bacon'}\n", - 'typesmethods': '\n' - 'Methods\n' - '*******\n' - '\n' - 'Methods are functions that are called using the attribute ' - 'notation.\n' - 'There are two flavors: built-in methods (such as "append()" ' - 'on lists)\n' - 'and class instance methods. Built-in methods are described ' - 'with the\n' - 'types that support them.\n' - '\n' - 'The implementation adds two special read-only attributes to ' - 'class\n' - 'instance methods: "m.im_self" is the object on which the ' - 'method\n' - 'operates, and "m.im_func" is the function implementing the ' - 'method.\n' - 'Calling "m(arg-1, arg-2, ..., arg-n)" is completely ' - 'equivalent to\n' - 'calling "m.im_func(m.im_self, arg-1, arg-2, ..., arg-n)".\n' - '\n' - 'Class instance methods are either *bound* or *unbound*, ' - 'referring to\n' - 'whether the method was accessed through an instance or a ' - 'class,\n' - 'respectively. When a method is unbound, its "im_self" ' - 'attribute will\n' - 'be "None" and if called, an explicit "self" object must be ' - 'passed as\n' - 'the first argument. In this case, "self" must be an ' - 'instance of the\n' - "unbound method's class (or a subclass of that class), " - 'otherwise a\n' - '"TypeError" is raised.\n' - '\n' - 'Like function objects, methods objects support getting ' - 'arbitrary\n' - 'attributes. However, since method attributes are actually ' - 'stored on\n' - 'the underlying function object ("meth.im_func"), setting ' - 'method\n' - 'attributes on either bound or unbound methods is ' - 'disallowed.\n' - 'Attempting to set an attribute on a method results in an\n' - '"AttributeError" being raised. In order to set a method ' - 'attribute,\n' - 'you need to explicitly set it on the underlying function ' - 'object:\n' - '\n' - ' >>> class C:\n' - ' ... def method(self):\n' - ' ... pass\n' - ' ...\n' - ' >>> c = C()\n' - " >>> c.method.whoami = 'my name is method' # can't set on " - 'the method\n' - ' Traceback (most recent call last):\n' - ' File "<stdin>", line 1, in <module>\n' - " AttributeError: 'instancemethod' object has no attribute " - "'whoami'\n" - " >>> c.method.im_func.whoami = 'my name is method'\n" - ' >>> c.method.whoami\n' - " 'my name is method'\n" - '\n' - 'See The standard type hierarchy for more information.\n', - 'typesmodules': '\n' - 'Modules\n' - '*******\n' - '\n' - 'The only special operation on a module is attribute access: ' - '"m.name",\n' - 'where *m* is a module and *name* accesses a name defined in ' - "*m*'s\n" - 'symbol table. Module attributes can be assigned to. (Note ' - 'that the\n' - '"import" statement is not, strictly speaking, an operation ' - 'on a module\n' - 'object; "import foo" does not require a module object named ' - '*foo* to\n' - 'exist, rather it requires an (external) *definition* for a ' - 'module\n' - 'named *foo* somewhere.)\n' - '\n' - 'A special attribute of every module is "__dict__". This is ' - 'the\n' - "dictionary containing the module's symbol table. Modifying " - 'this\n' - "dictionary will actually change the module's symbol table, " - 'but direct\n' - 'assignment to the "__dict__" attribute is not possible (you ' - 'can write\n' - '"m.__dict__[\'a\'] = 1", which defines "m.a" to be "1", but ' - "you can't\n" - 'write "m.__dict__ = {}"). Modifying "__dict__" directly is ' - 'not\n' - 'recommended.\n' - '\n' - 'Modules built into the interpreter are written like this: ' - '"<module\n' - '\'sys\' (built-in)>". If loaded from a file, they are ' - 'written as\n' - '"<module \'os\' from ' - '\'/usr/local/lib/pythonX.Y/os.pyc\'>".\n', - 'typesseq': '\n' - 'Sequence Types --- "str", "unicode", "list", "tuple", ' - '"bytearray", "buffer", "xrange"\n' - '*************************************************************************************\n' - '\n' - 'There are seven sequence types: strings, Unicode strings, ' - 'lists,\n' - 'tuples, bytearrays, buffers, and xrange objects.\n' - '\n' - 'For other containers see the built in "dict" and "set" classes, ' - 'and\n' - 'the "collections" module.\n' - '\n' - 'String literals are written in single or double quotes: ' - '"\'xyzzy\'",\n' - '""frobozz"". See String literals for more about string ' - 'literals.\n' - 'Unicode strings are much like strings, but are specified in the ' - 'syntax\n' - 'using a preceding "\'u\'" character: "u\'abc\'", "u"def"". In ' - 'addition to\n' - 'the functionality described here, there are also ' - 'string-specific\n' - 'methods described in the String Methods section. Lists are ' - 'constructed\n' - 'with square brackets, separating items with commas: "[a, b, ' - 'c]".\n' - 'Tuples are constructed by the comma operator (not within square\n' - 'brackets), with or without enclosing parentheses, but an empty ' - 'tuple\n' - 'must have the enclosing parentheses, such as "a, b, c" or "()". ' - 'A\n' - 'single item tuple must have a trailing comma, such as "(d,)".\n' - '\n' - 'Bytearray objects are created with the built-in function\n' - '"bytearray()".\n' - '\n' - 'Buffer objects are not directly supported by Python syntax, but ' - 'can be\n' - 'created by calling the built-in function "buffer()". They ' - "don't\n" - 'support concatenation or repetition.\n' - '\n' - 'Objects of type xrange are similar to buffers in that there is ' - 'no\n' - 'specific syntax to create them, but they are created using the\n' - '"xrange()" function. They don\'t support slicing, concatenation ' - 'or\n' - 'repetition, and using "in", "not in", "min()" or "max()" on them ' - 'is\n' - 'inefficient.\n' - '\n' - 'Most sequence types support the following operations. The "in" ' - 'and\n' - '"not in" operations have the same priorities as the comparison\n' - 'operations. The "+" and "*" operations have the same priority ' - 'as the\n' - 'corresponding numeric operations. [3] Additional methods are ' - 'provided\n' - 'for Mutable Sequence Types.\n' - '\n' - 'This table lists the sequence operations sorted in ascending ' - 'priority.\n' - 'In the table, *s* and *t* are sequences of the same type; *n*, ' - '*i* and\n' - '*j* are integers:\n' - '\n' - '+--------------------+----------------------------------+------------+\n' - '| Operation | Result | ' - 'Notes |\n' - '+====================+==================================+============+\n' - '| "x in s" | "True" if an item of *s* is | ' - '(1) |\n' - '| | equal to *x*, else "False" ' - '| |\n' - '+--------------------+----------------------------------+------------+\n' - '| "x not in s" | "False" if an item of *s* is | ' - '(1) |\n' - '| | equal to *x*, else "True" ' - '| |\n' - '+--------------------+----------------------------------+------------+\n' - '| "s + t" | the concatenation of *s* and *t* | ' - '(6) |\n' - '+--------------------+----------------------------------+------------+\n' - '| "s * n, n * s" | equivalent to adding *s* to | ' - '(2) |\n' - '| | itself *n* times ' - '| |\n' - '+--------------------+----------------------------------+------------+\n' - '| "s[i]" | *i*th item of *s*, origin 0 | ' - '(3) |\n' - '+--------------------+----------------------------------+------------+\n' - '| "s[i:j]" | slice of *s* from *i* to *j* | ' - '(3)(4) |\n' - '+--------------------+----------------------------------+------------+\n' - '| "s[i:j:k]" | slice of *s* from *i* to *j* | ' - '(3)(5) |\n' - '| | with step *k* ' - '| |\n' - '+--------------------+----------------------------------+------------+\n' - '| "len(s)" | length of *s* ' - '| |\n' - '+--------------------+----------------------------------+------------+\n' - '| "min(s)" | smallest item of *s* ' - '| |\n' - '+--------------------+----------------------------------+------------+\n' - '| "max(s)" | largest item of *s* ' - '| |\n' - '+--------------------+----------------------------------+------------+\n' - '| "s.index(x)" | index of the first occurrence of ' - '| |\n' - '| | *x* in *s* ' - '| |\n' - '+--------------------+----------------------------------+------------+\n' - '| "s.count(x)" | total number of occurrences of ' - '| |\n' - '| | *x* in *s* ' - '| |\n' - '+--------------------+----------------------------------+------------+\n' - '\n' - 'Sequence types also support comparisons. In particular, tuples ' - 'and\n' - 'lists are compared lexicographically by comparing corresponding\n' - 'elements. This means that to compare equal, every element must ' - 'compare\n' - 'equal and the two sequences must be of the same type and have ' - 'the same\n' - 'length. (For full details see Comparisons in the language ' - 'reference.)\n' - '\n' - 'Notes:\n' - '\n' - '1. When *s* is a string or Unicode string object the "in" and ' - '"not\n' - ' in" operations act like a substring test. In Python ' - 'versions\n' - ' before 2.3, *x* had to be a string of length 1. In Python 2.3 ' - 'and\n' - ' beyond, *x* may be a string of any length.\n' - '\n' - '2. Values of *n* less than "0" are treated as "0" (which yields ' - 'an\n' - ' empty sequence of the same type as *s*). Note that items in ' - 'the\n' - ' sequence *s* are not copied; they are referenced multiple ' - 'times.\n' - ' This often haunts new Python programmers; consider:\n' - '\n' - ' >>> lists = [[]] * 3\n' - ' >>> lists\n' - ' [[], [], []]\n' - ' >>> lists[0].append(3)\n' - ' >>> lists\n' - ' [[3], [3], [3]]\n' - '\n' - ' What has happened is that "[[]]" is a one-element list ' - 'containing\n' - ' an empty list, so all three elements of "[[]] * 3" are ' - 'references\n' - ' to this single empty list. Modifying any of the elements of\n' - ' "lists" modifies this single list. You can create a list of\n' - ' different lists this way:\n' - '\n' - ' >>> lists = [[] for i in range(3)]\n' - ' >>> lists[0].append(3)\n' - ' >>> lists[1].append(5)\n' - ' >>> lists[2].append(7)\n' - ' >>> lists\n' - ' [[3], [5], [7]]\n' - '\n' - ' Further explanation is available in the FAQ entry How do I ' - 'create a\n' - ' multidimensional list?.\n' - '\n' - '3. If *i* or *j* is negative, the index is relative to the end ' - 'of\n' - ' sequence *s*: "len(s) + i" or "len(s) + j" is substituted. ' - 'But\n' - ' note that "-0" is still "0".\n' - '\n' - '4. The slice of *s* from *i* to *j* is defined as the sequence ' - 'of\n' - ' items with index *k* such that "i <= k < j". If *i* or *j* ' - 'is\n' - ' greater than "len(s)", use "len(s)". If *i* is omitted or ' - '"None",\n' - ' use "0". If *j* is omitted or "None", use "len(s)". If *i* ' - 'is\n' - ' greater than or equal to *j*, the slice is empty.\n' - '\n' - '5. The slice of *s* from *i* to *j* with step *k* is defined as ' - 'the\n' - ' sequence of items with index "x = i + n*k" such that "0 <= n ' - '<\n' - ' (j-i)/k". In other words, the indices are "i", "i+k", ' - '"i+2*k",\n' - ' "i+3*k" and so on, stopping when *j* is reached (but never\n' - ' including *j*). When *k* is positive, *i* and *j* are ' - 'reduced to\n' - ' "len(s)" if they are greater. When *k* is negative, *i* and ' - '*j* are\n' - ' reduced to "len(s) - 1" if they are greater. If *i* or *j* ' - 'are\n' - ' omitted or "None", they become "end" values (which end ' - 'depends on\n' - ' the sign of *k*). Note, *k* cannot be zero. If *k* is ' - '"None", it\n' - ' is treated like "1".\n' - '\n' - '6. **CPython implementation detail:** If *s* and *t* are both\n' - ' strings, some Python implementations such as CPython can ' - 'usually\n' - ' perform an in-place optimization for assignments of the form ' - '"s = s\n' - ' + t" or "s += t". When applicable, this optimization makes\n' - ' quadratic run-time much less likely. This optimization is ' - 'both\n' - ' version and implementation dependent. For performance ' - 'sensitive\n' - ' code, it is preferable to use the "str.join()" method which ' - 'assures\n' - ' consistent linear concatenation performance across versions ' - 'and\n' - ' implementations.\n' - '\n' - ' Changed in version 2.4: Formerly, string concatenation never\n' - ' occurred in-place.\n' - '\n' - '\n' - 'String Methods\n' - '==============\n' - '\n' - 'Below are listed the string methods which both 8-bit strings ' - 'and\n' - 'Unicode objects support. Some of them are also available on\n' - '"bytearray" objects.\n' - '\n' - "In addition, Python's strings support the sequence type methods\n" - 'described in the Sequence Types --- str, unicode, list, tuple,\n' - 'bytearray, buffer, xrange section. To output formatted strings ' - 'use\n' - 'template strings or the "%" operator described in the String\n' - 'Formatting Operations section. Also, see the "re" module for ' - 'string\n' - 'functions based on regular expressions.\n' - '\n' - 'str.capitalize()\n' - '\n' - ' Return a copy of the string with its first character ' - 'capitalized\n' - ' and the rest lowercased.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.center(width[, fillchar])\n' - '\n' - ' Return centered in a string of length *width*. Padding is ' - 'done\n' - ' using the specified *fillchar* (default is a space).\n' - '\n' - ' Changed in version 2.4: Support for the *fillchar* argument.\n' - '\n' - 'str.count(sub[, start[, end]])\n' - '\n' - ' Return the number of non-overlapping occurrences of substring ' - '*sub*\n' - ' in the range [*start*, *end*]. Optional arguments *start* ' - 'and\n' - ' *end* are interpreted as in slice notation.\n' - '\n' - 'str.decode([encoding[, errors]])\n' - '\n' - ' Decodes the string using the codec registered for ' - '*encoding*.\n' - ' *encoding* defaults to the default string encoding. *errors* ' - 'may\n' - ' be given to set a different error handling scheme. The ' - 'default is\n' - ' "\'strict\'", meaning that encoding errors raise ' - '"UnicodeError".\n' - ' Other possible values are "\'ignore\'", "\'replace\'" and any ' - 'other\n' - ' name registered via "codecs.register_error()", see section ' - 'Codec\n' - ' Base Classes.\n' - '\n' - ' New in version 2.2.\n' - '\n' - ' Changed in version 2.3: Support for other error handling ' - 'schemes\n' - ' added.\n' - '\n' - ' Changed in version 2.7: Support for keyword arguments added.\n' - '\n' - 'str.encode([encoding[, errors]])\n' - '\n' - ' Return an encoded version of the string. Default encoding is ' - 'the\n' - ' current default string encoding. *errors* may be given to ' - 'set a\n' - ' different error handling scheme. The default for *errors* ' - 'is\n' - ' "\'strict\'", meaning that encoding errors raise a ' - '"UnicodeError".\n' - ' Other possible values are "\'ignore\'", "\'replace\'",\n' - ' "\'xmlcharrefreplace\'", "\'backslashreplace\'" and any other ' - 'name\n' - ' registered via "codecs.register_error()", see section Codec ' - 'Base\n' - ' Classes. For a list of possible encodings, see section ' - 'Standard\n' - ' Encodings.\n' - '\n' - ' New in version 2.0.\n' - '\n' - ' Changed in version 2.3: Support for "\'xmlcharrefreplace\'" ' - 'and\n' - ' "\'backslashreplace\'" and other error handling schemes ' - 'added.\n' - '\n' - ' Changed in version 2.7: Support for keyword arguments added.\n' - '\n' - 'str.endswith(suffix[, start[, end]])\n' - '\n' - ' Return "True" if the string ends with the specified ' - '*suffix*,\n' - ' otherwise return "False". *suffix* can also be a tuple of ' - 'suffixes\n' - ' to look for. With optional *start*, test beginning at that\n' - ' position. With optional *end*, stop comparing at that ' - 'position.\n' - '\n' - ' Changed in version 2.5: Accept tuples as *suffix*.\n' - '\n' - 'str.expandtabs([tabsize])\n' - '\n' - ' Return a copy of the string where all tab characters are ' - 'replaced\n' - ' by one or more spaces, depending on the current column and ' - 'the\n' - ' given tab size. Tab positions occur every *tabsize* ' - 'characters\n' - ' (default is 8, giving tab positions at columns 0, 8, 16 and ' - 'so on).\n' - ' To expand the string, the current column is set to zero and ' - 'the\n' - ' string is examined character by character. If the character ' - 'is a\n' - ' tab ("\\t"), one or more space characters are inserted in the ' - 'result\n' - ' until the current column is equal to the next tab position. ' - '(The\n' - ' tab character itself is not copied.) If the character is a ' - 'newline\n' - ' ("\\n") or return ("\\r"), it is copied and the current ' - 'column is\n' - ' reset to zero. Any other character is copied unchanged and ' - 'the\n' - ' current column is incremented by one regardless of how the\n' - ' character is represented when printed.\n' - '\n' - " >>> '01\\t012\\t0123\\t01234'.expandtabs()\n" - " '01 012 0123 01234'\n" - " >>> '01\\t012\\t0123\\t01234'.expandtabs(4)\n" - " '01 012 0123 01234'\n" - '\n' - 'str.find(sub[, start[, end]])\n' - '\n' - ' Return the lowest index in the string where substring *sub* ' - 'is\n' - ' found within the slice "s[start:end]". Optional arguments ' - '*start*\n' - ' and *end* are interpreted as in slice notation. Return "-1" ' - 'if\n' - ' *sub* is not found.\n' - '\n' - ' Note: The "find()" method should be used only if you need to ' - 'know\n' - ' the position of *sub*. To check if *sub* is a substring or ' - 'not,\n' - ' use the "in" operator:\n' - '\n' - " >>> 'Py' in 'Python'\n" - ' True\n' - '\n' - 'str.format(*args, **kwargs)\n' - '\n' - ' Perform a string formatting operation. The string on which ' - 'this\n' - ' method is called can contain literal text or replacement ' - 'fields\n' - ' delimited by braces "{}". Each replacement field contains ' - 'either\n' - ' the numeric index of a positional argument, or the name of a\n' - ' keyword argument. Returns a copy of the string where each\n' - ' replacement field is replaced with the string value of the\n' - ' corresponding argument.\n' - '\n' - ' >>> "The sum of 1 + 2 is {0}".format(1+2)\n' - " 'The sum of 1 + 2 is 3'\n" - '\n' - ' See Format String Syntax for a description of the various\n' - ' formatting options that can be specified in format strings.\n' - '\n' - ' This method of string formatting is the new standard in ' - 'Python 3,\n' - ' and should be preferred to the "%" formatting described in ' - 'String\n' - ' Formatting Operations in new code.\n' - '\n' - ' New in version 2.6.\n' - '\n' - 'str.index(sub[, start[, end]])\n' - '\n' - ' Like "find()", but raise "ValueError" when the substring is ' - 'not\n' - ' found.\n' - '\n' - 'str.isalnum()\n' - '\n' - ' Return true if all characters in the string are alphanumeric ' - 'and\n' - ' there is at least one character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.isalpha()\n' - '\n' - ' Return true if all characters in the string are alphabetic ' - 'and\n' - ' there is at least one character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.isdigit()\n' - '\n' - ' Return true if all characters in the string are digits and ' - 'there is\n' - ' at least one character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.islower()\n' - '\n' - ' Return true if all cased characters [4] in the string are ' - 'lowercase\n' - ' and there is at least one cased character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.isspace()\n' - '\n' - ' Return true if there are only whitespace characters in the ' - 'string\n' - ' and there is at least one character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.istitle()\n' - '\n' - ' Return true if the string is a titlecased string and there is ' - 'at\n' - ' least one character, for example uppercase characters may ' - 'only\n' - ' follow uncased characters and lowercase characters only cased ' - 'ones.\n' - ' Return false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.isupper()\n' - '\n' - ' Return true if all cased characters [4] in the string are ' - 'uppercase\n' - ' and there is at least one cased character, false otherwise.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.join(iterable)\n' - '\n' - ' Return a string which is the concatenation of the strings in\n' - ' *iterable*. A "TypeError" will be raised if there are any ' - 'non-\n' - ' string values in *iterable*, including "bytes" objects. The\n' - ' separator between elements is the string providing this ' - 'method.\n' - '\n' - 'str.ljust(width[, fillchar])\n' - '\n' - ' Return the string left justified in a string of length ' - '*width*.\n' - ' Padding is done using the specified *fillchar* (default is a\n' - ' space). The original string is returned if *width* is less ' - 'than or\n' - ' equal to "len(s)".\n' - '\n' - ' Changed in version 2.4: Support for the *fillchar* argument.\n' - '\n' - 'str.lower()\n' - '\n' - ' Return a copy of the string with all the cased characters ' - '[4]\n' - ' converted to lowercase.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.lstrip([chars])\n' - '\n' - ' Return a copy of the string with leading characters removed. ' - 'The\n' - ' *chars* argument is a string specifying the set of characters ' - 'to be\n' - ' removed. If omitted or "None", the *chars* argument defaults ' - 'to\n' - ' removing whitespace. The *chars* argument is not a prefix; ' - 'rather,\n' - ' all combinations of its values are stripped:\n' - '\n' - " >>> ' spacious '.lstrip()\n" - " 'spacious '\n" - " >>> 'www.example.com'.lstrip('cmowz.')\n" - " 'example.com'\n" - '\n' - ' Changed in version 2.2.2: Support for the *chars* argument.\n' - '\n' - 'str.partition(sep)\n' - '\n' - ' Split the string at the first occurrence of *sep*, and return ' - 'a\n' - ' 3-tuple containing the part before the separator, the ' - 'separator\n' - ' itself, and the part after the separator. If the separator ' - 'is not\n' - ' found, return a 3-tuple containing the string itself, ' - 'followed by\n' - ' two empty strings.\n' - '\n' - ' New in version 2.5.\n' - '\n' - 'str.replace(old, new[, count])\n' - '\n' - ' Return a copy of the string with all occurrences of substring ' - '*old*\n' - ' replaced by *new*. If the optional argument *count* is ' - 'given, only\n' - ' the first *count* occurrences are replaced.\n' - '\n' - 'str.rfind(sub[, start[, end]])\n' - '\n' - ' Return the highest index in the string where substring *sub* ' - 'is\n' - ' found, such that *sub* is contained within "s[start:end]".\n' - ' Optional arguments *start* and *end* are interpreted as in ' - 'slice\n' - ' notation. Return "-1" on failure.\n' - '\n' - 'str.rindex(sub[, start[, end]])\n' - '\n' - ' Like "rfind()" but raises "ValueError" when the substring ' - '*sub* is\n' - ' not found.\n' - '\n' - 'str.rjust(width[, fillchar])\n' - '\n' - ' Return the string right justified in a string of length ' - '*width*.\n' - ' Padding is done using the specified *fillchar* (default is a\n' - ' space). The original string is returned if *width* is less ' - 'than or\n' - ' equal to "len(s)".\n' - '\n' - ' Changed in version 2.4: Support for the *fillchar* argument.\n' - '\n' - 'str.rpartition(sep)\n' - '\n' - ' Split the string at the last occurrence of *sep*, and return ' - 'a\n' - ' 3-tuple containing the part before the separator, the ' - 'separator\n' - ' itself, and the part after the separator. If the separator ' - 'is not\n' - ' found, return a 3-tuple containing two empty strings, ' - 'followed by\n' - ' the string itself.\n' - '\n' - ' New in version 2.5.\n' - '\n' - 'str.rsplit([sep[, maxsplit]])\n' - '\n' - ' Return a list of the words in the string, using *sep* as the\n' - ' delimiter string. If *maxsplit* is given, at most *maxsplit* ' - 'splits\n' - ' are done, the *rightmost* ones. If *sep* is not specified ' - 'or\n' - ' "None", any whitespace string is a separator. Except for ' - 'splitting\n' - ' from the right, "rsplit()" behaves like "split()" which is\n' - ' described in detail below.\n' - '\n' - ' New in version 2.4.\n' - '\n' - 'str.rstrip([chars])\n' - '\n' - ' Return a copy of the string with trailing characters ' - 'removed. The\n' - ' *chars* argument is a string specifying the set of characters ' - 'to be\n' - ' removed. If omitted or "None", the *chars* argument defaults ' - 'to\n' - ' removing whitespace. The *chars* argument is not a suffix; ' - 'rather,\n' - ' all combinations of its values are stripped:\n' - '\n' - " >>> ' spacious '.rstrip()\n" - " ' spacious'\n" - " >>> 'mississippi'.rstrip('ipz')\n" - " 'mississ'\n" - '\n' - ' Changed in version 2.2.2: Support for the *chars* argument.\n' - '\n' - 'str.split([sep[, maxsplit]])\n' - '\n' - ' Return a list of the words in the string, using *sep* as the\n' - ' delimiter string. If *maxsplit* is given, at most ' - '*maxsplit*\n' - ' splits are done (thus, the list will have at most ' - '"maxsplit+1"\n' - ' elements). If *maxsplit* is not specified or "-1", then ' - 'there is\n' - ' no limit on the number of splits (all possible splits are ' - 'made).\n' - '\n' - ' If *sep* is given, consecutive delimiters are not grouped ' - 'together\n' - ' and are deemed to delimit empty strings (for example,\n' - ' "\'1,,2\'.split(\',\')" returns "[\'1\', \'\', \'2\']"). The ' - '*sep* argument\n' - ' may consist of multiple characters (for example,\n' - ' "\'1<>2<>3\'.split(\'<>\')" returns "[\'1\', \'2\', \'3\']"). ' - 'Splitting an\n' - ' empty string with a specified separator returns "[\'\']".\n' - '\n' - ' If *sep* is not specified or is "None", a different ' - 'splitting\n' - ' algorithm is applied: runs of consecutive whitespace are ' - 'regarded\n' - ' as a single separator, and the result will contain no empty ' - 'strings\n' - ' at the start or end if the string has leading or trailing\n' - ' whitespace. Consequently, splitting an empty string or a ' - 'string\n' - ' consisting of just whitespace with a "None" separator returns ' - '"[]".\n' - '\n' - ' For example, "\' 1 2 3 \'.split()" returns "[\'1\', ' - '\'2\', \'3\']", and\n' - ' "\' 1 2 3 \'.split(None, 1)" returns "[\'1\', \'2 3 ' - '\']".\n' - '\n' - 'str.splitlines([keepends])\n' - '\n' - ' Return a list of the lines in the string, breaking at line\n' - ' boundaries. This method uses the *universal newlines* ' - 'approach to\n' - ' splitting lines. Line breaks are not included in the ' - 'resulting list\n' - ' unless *keepends* is given and true.\n' - '\n' - ' Python recognizes ""\\r"", ""\\n"", and ""\\r\\n"" as line ' - 'boundaries\n' - ' for 8-bit strings.\n' - '\n' - ' For example:\n' - '\n' - " >>> 'ab c\\n\\nde fg\\rkl\\r\\n'.splitlines()\n" - " ['ab c', '', 'de fg', 'kl']\n" - " >>> 'ab c\\n\\nde fg\\rkl\\r\\n'.splitlines(True)\n" - " ['ab c\\n', '\\n', 'de fg\\r', 'kl\\r\\n']\n" - '\n' - ' Unlike "split()" when a delimiter string *sep* is given, ' - 'this\n' - ' method returns an empty list for the empty string, and a ' - 'terminal\n' - ' line break does not result in an extra line:\n' - '\n' - ' >>> "".splitlines()\n' - ' []\n' - ' >>> "One line\\n".splitlines()\n' - " ['One line']\n" - '\n' - ' For comparison, "split(\'\\n\')" gives:\n' - '\n' - " >>> ''.split('\\n')\n" - " ['']\n" - " >>> 'Two lines\\n'.split('\\n')\n" - " ['Two lines', '']\n" - '\n' - 'unicode.splitlines([keepends])\n' - '\n' - ' Return a list of the lines in the string, like ' - '"str.splitlines()".\n' - ' However, the Unicode method splits on the following line\n' - ' boundaries, which are a superset of the *universal newlines*\n' - ' recognized for 8-bit strings.\n' - '\n' - ' +-------------------------+-------------------------------+\n' - ' | Representation | Description |\n' - ' +=========================+===============================+\n' - ' | "\\n" | Line Feed |\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\r" | Carriage Return |\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\r\\n" | Carriage Return + Line Feed ' - '|\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\v" or "\\x0b" | Line Tabulation ' - '|\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\f" or "\\x0c" | Form Feed ' - '|\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\x1c" | File Separator |\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\x1d" | Group Separator |\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\x1e" | Record Separator |\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\x85" | Next Line (C1 Control Code) |\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\u2028" | Line Separator |\n' - ' +-------------------------+-------------------------------+\n' - ' | "\\u2029" | Paragraph Separator |\n' - ' +-------------------------+-------------------------------+\n' - '\n' - ' Changed in version 2.7: "\\v" and "\\f" added to list of ' - 'line\n' - ' boundaries.\n' - '\n' - 'str.startswith(prefix[, start[, end]])\n' - '\n' - ' Return "True" if string starts with the *prefix*, otherwise ' - 'return\n' - ' "False". *prefix* can also be a tuple of prefixes to look ' - 'for.\n' - ' With optional *start*, test string beginning at that ' - 'position.\n' - ' With optional *end*, stop comparing string at that position.\n' - '\n' - ' Changed in version 2.5: Accept tuples as *prefix*.\n' - '\n' - 'str.strip([chars])\n' - '\n' - ' Return a copy of the string with the leading and trailing\n' - ' characters removed. The *chars* argument is a string ' - 'specifying the\n' - ' set of characters to be removed. If omitted or "None", the ' - '*chars*\n' - ' argument defaults to removing whitespace. The *chars* ' - 'argument is\n' - ' not a prefix or suffix; rather, all combinations of its ' - 'values are\n' - ' stripped:\n' - '\n' - " >>> ' spacious '.strip()\n" - " 'spacious'\n" - " >>> 'www.example.com'.strip('cmowz.')\n" - " 'example'\n" - '\n' - ' Changed in version 2.2.2: Support for the *chars* argument.\n' - '\n' - 'str.swapcase()\n' - '\n' - ' Return a copy of the string with uppercase characters ' - 'converted to\n' - ' lowercase and vice versa.\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.title()\n' - '\n' - ' Return a titlecased version of the string where words start ' - 'with an\n' - ' uppercase character and the remaining characters are ' - 'lowercase.\n' - '\n' - ' The algorithm uses a simple language-independent definition ' - 'of a\n' - ' word as groups of consecutive letters. The definition works ' - 'in\n' - ' many contexts but it means that apostrophes in contractions ' - 'and\n' - ' possessives form word boundaries, which may not be the ' - 'desired\n' - ' result:\n' - '\n' - ' >>> "they\'re bill\'s friends from the UK".title()\n' - ' "They\'Re Bill\'S Friends From The Uk"\n' - '\n' - ' A workaround for apostrophes can be constructed using ' - 'regular\n' - ' expressions:\n' - '\n' - ' >>> import re\n' - ' >>> def titlecase(s):\n' - ' ... return re.sub(r"[A-Za-z]+(\'[A-Za-z]+)?",\n' - ' ... lambda mo: mo.group(0)[0].upper() +\n' - ' ... mo.group(0)[1:].lower(),\n' - ' ... s)\n' - ' ...\n' - ' >>> titlecase("they\'re bill\'s friends.")\n' - ' "They\'re Bill\'s Friends."\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.translate(table[, deletechars])\n' - '\n' - ' Return a copy of the string where all characters occurring in ' - 'the\n' - ' optional argument *deletechars* are removed, and the ' - 'remaining\n' - ' characters have been mapped through the given translation ' - 'table,\n' - ' which must be a string of length 256.\n' - '\n' - ' You can use the "maketrans()" helper function in the ' - '"string"\n' - ' module to create a translation table. For string objects, set ' - 'the\n' - ' *table* argument to "None" for translations that only delete\n' - ' characters:\n' - '\n' - " >>> 'read this short text'.translate(None, 'aeiou')\n" - " 'rd ths shrt txt'\n" - '\n' - ' New in version 2.6: Support for a "None" *table* argument.\n' - '\n' - ' For Unicode objects, the "translate()" method does not accept ' - 'the\n' - ' optional *deletechars* argument. Instead, it returns a copy ' - 'of the\n' - ' *s* where all characters have been mapped through the given\n' - ' translation table which must be a mapping of Unicode ordinals ' - 'to\n' - ' Unicode ordinals, Unicode strings or "None". Unmapped ' - 'characters\n' - ' are left untouched. Characters mapped to "None" are deleted. ' - 'Note,\n' - ' a more flexible approach is to create a custom character ' - 'mapping\n' - ' codec using the "codecs" module (see "encodings.cp1251" for ' - 'an\n' - ' example).\n' - '\n' - 'str.upper()\n' - '\n' - ' Return a copy of the string with all the cased characters ' - '[4]\n' - ' converted to uppercase. Note that "str.upper().isupper()" ' - 'might be\n' - ' "False" if "s" contains uncased characters or if the Unicode\n' - ' category of the resulting character(s) is not "Lu" (Letter,\n' - ' uppercase), but e.g. "Lt" (Letter, titlecase).\n' - '\n' - ' For 8-bit strings, this method is locale-dependent.\n' - '\n' - 'str.zfill(width)\n' - '\n' - ' Return the numeric string left filled with zeros in a string ' - 'of\n' - ' length *width*. A sign prefix is handled correctly. The ' - 'original\n' - ' string is returned if *width* is less than or equal to ' - '"len(s)".\n' - '\n' - ' New in version 2.2.2.\n' - '\n' - 'The following methods are present only on unicode objects:\n' - '\n' - 'unicode.isnumeric()\n' - '\n' - ' Return "True" if there are only numeric characters in S, ' - '"False"\n' - ' otherwise. Numeric characters include digit characters, and ' - 'all\n' - ' characters that have the Unicode numeric value property, ' - 'e.g.\n' - ' U+2155, VULGAR FRACTION ONE FIFTH.\n' - '\n' - 'unicode.isdecimal()\n' - '\n' - ' Return "True" if there are only decimal characters in S, ' - '"False"\n' - ' otherwise. Decimal characters include digit characters, and ' - 'all\n' - ' characters that can be used to form decimal-radix numbers, ' - 'e.g.\n' - ' U+0660, ARABIC-INDIC DIGIT ZERO.\n' - '\n' - '\n' - 'String Formatting Operations\n' - '============================\n' - '\n' - 'String and Unicode objects have one unique built-in operation: ' - 'the "%"\n' - 'operator (modulo). This is also known as the string ' - '*formatting* or\n' - '*interpolation* operator. Given "format % values" (where ' - '*format* is\n' - 'a string or Unicode object), "%" conversion specifications in ' - '*format*\n' - 'are replaced with zero or more elements of *values*. The effect ' - 'is\n' - 'similar to the using "sprintf()" in the C language. If *format* ' - 'is a\n' - 'Unicode object, or if any of the objects being converted using ' - 'the\n' - '"%s" conversion are Unicode objects, the result will also be a ' - 'Unicode\n' - 'object.\n' - '\n' - 'If *format* requires a single argument, *values* may be a single ' - 'non-\n' - 'tuple object. [5] Otherwise, *values* must be a tuple with ' - 'exactly\n' - 'the number of items specified by the format string, or a single\n' - 'mapping object (for example, a dictionary).\n' - '\n' - 'A conversion specifier contains two or more characters and has ' - 'the\n' - 'following components, which must occur in this order:\n' - '\n' - '1. The "\'%\'" character, which marks the start of the ' - 'specifier.\n' - '\n' - '2. Mapping key (optional), consisting of a parenthesised ' - 'sequence\n' - ' of characters (for example, "(somename)").\n' - '\n' - '3. Conversion flags (optional), which affect the result of some\n' - ' conversion types.\n' - '\n' - '4. Minimum field width (optional). If specified as an "\'*\'"\n' - ' (asterisk), the actual width is read from the next element of ' - 'the\n' - ' tuple in *values*, and the object to convert comes after the\n' - ' minimum field width and optional precision.\n' - '\n' - '5. Precision (optional), given as a "\'.\'" (dot) followed by ' - 'the\n' - ' precision. If specified as "\'*\'" (an asterisk), the actual ' - 'width\n' - ' is read from the next element of the tuple in *values*, and ' - 'the\n' - ' value to convert comes after the precision.\n' - '\n' - '6. Length modifier (optional).\n' - '\n' - '7. Conversion type.\n' - '\n' - 'When the right argument is a dictionary (or other mapping type), ' - 'then\n' - 'the formats in the string *must* include a parenthesised mapping ' - 'key\n' - 'into that dictionary inserted immediately after the "\'%\'" ' - 'character.\n' - 'The mapping key selects the value to be formatted from the ' - 'mapping.\n' - 'For example:\n' - '\n' - ">>> print '%(language)s has %(number)03d quote types.' % \\\n" - '... {"language": "Python", "number": 2}\n' - 'Python has 002 quote types.\n' - '\n' - 'In this case no "*" specifiers may occur in a format (since ' - 'they\n' - 'require a sequential parameter list).\n' - '\n' - 'The conversion flag characters are:\n' - '\n' - '+-----------+-----------------------------------------------------------------------+\n' - '| Flag | ' - 'Meaning ' - '|\n' - '+===========+=======================================================================+\n' - '| "\'#\'" | The value conversion will use the "alternate ' - 'form" (where defined |\n' - '| | ' - 'below). ' - '|\n' - '+-----------+-----------------------------------------------------------------------+\n' - '| "\'0\'" | The conversion will be zero padded for numeric ' - 'values. |\n' - '+-----------+-----------------------------------------------------------------------+\n' - '| "\'-\'" | The converted value is left adjusted (overrides ' - 'the "\'0\'" conversion |\n' - '| | if both are ' - 'given). |\n' - '+-----------+-----------------------------------------------------------------------+\n' - '| "\' \'" | (a space) A blank should be left before a ' - 'positive number (or empty |\n' - '| | string) produced by a signed ' - 'conversion. |\n' - '+-----------+-----------------------------------------------------------------------+\n' - '| "\'+\'" | A sign character ("\'+\'" or "\'-\'") will ' - 'precede the conversion |\n' - '| | (overrides a "space" ' - 'flag). |\n' - '+-----------+-----------------------------------------------------------------------+\n' - '\n' - 'A length modifier ("h", "l", or "L") may be present, but is ' - 'ignored as\n' - 'it is not necessary for Python -- so e.g. "%ld" is identical to ' - '"%d".\n' - '\n' - 'The conversion types are:\n' - '\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| Conversion | ' - 'Meaning | Notes ' - '|\n' - '+==============+=======================================================+=========+\n' - '| "\'d\'" | Signed integer ' - 'decimal. | |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'i\'" | Signed integer ' - 'decimal. | |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'o\'" | Signed octal ' - 'value. | (1) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'u\'" | Obsolete type -- it is identical to ' - '"\'d\'". | (7) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'x\'" | Signed hexadecimal ' - '(lowercase). | (2) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'X\'" | Signed hexadecimal ' - '(uppercase). | (2) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'e\'" | Floating point exponential format ' - '(lowercase). | (3) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'E\'" | Floating point exponential format ' - '(uppercase). | (3) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'f\'" | Floating point decimal ' - 'format. | (3) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'F\'" | Floating point decimal ' - 'format. | (3) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'g\'" | Floating point format. Uses lowercase ' - 'exponential | (4) |\n' - '| | format if exponent is less than -4 or not less ' - 'than | |\n' - '| | precision, decimal format ' - 'otherwise. | |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'G\'" | Floating point format. Uses uppercase ' - 'exponential | (4) |\n' - '| | format if exponent is less than -4 or not less ' - 'than | |\n' - '| | precision, decimal format ' - 'otherwise. | |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'c\'" | Single character (accepts integer or single ' - 'character | |\n' - '| | ' - 'string). | ' - '|\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'r\'" | String (converts any Python object using ' - 'repr()). | (5) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'s\'" | String (converts any Python object using ' - '"str()"). | (6) |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '| "\'%\'" | No argument is converted, results in a ' - '"\'%\'" | |\n' - '| | character in the ' - 'result. | |\n' - '+--------------+-------------------------------------------------------+---------+\n' - '\n' - 'Notes:\n' - '\n' - '1. The alternate form causes a leading zero ("\'0\'") to be ' - 'inserted\n' - ' between left-hand padding and the formatting of the number if ' - 'the\n' - ' leading character of the result is not already a zero.\n' - '\n' - '2. The alternate form causes a leading "\'0x\'" or "\'0X\'" ' - '(depending\n' - ' on whether the "\'x\'" or "\'X\'" format was used) to be ' - 'inserted\n' - ' before the first digit.\n' - '\n' - '3. The alternate form causes the result to always contain a ' - 'decimal\n' - ' point, even if no digits follow it.\n' - '\n' - ' The precision determines the number of digits after the ' - 'decimal\n' - ' point and defaults to 6.\n' - '\n' - '4. The alternate form causes the result to always contain a ' - 'decimal\n' - ' point, and trailing zeroes are not removed as they would ' - 'otherwise\n' - ' be.\n' - '\n' - ' The precision determines the number of significant digits ' - 'before\n' - ' and after the decimal point and defaults to 6.\n' - '\n' - '5. The "%r" conversion was added in Python 2.0.\n' - '\n' - ' The precision determines the maximal number of characters ' - 'used.\n' - '\n' - '6. If the object or format provided is a "unicode" string, the\n' - ' resulting string will also be "unicode".\n' - '\n' - ' The precision determines the maximal number of characters ' - 'used.\n' - '\n' - '7. See **PEP 237**.\n' - '\n' - 'Since Python strings have an explicit length, "%s" conversions ' - 'do not\n' - 'assume that "\'\\0\'" is the end of the string.\n' - '\n' - 'Changed in version 2.7: "%f" conversions for numbers whose ' - 'absolute\n' - 'value is over 1e50 are no longer replaced by "%g" conversions.\n' - '\n' - 'Additional string operations are defined in standard modules ' - '"string"\n' - 'and "re".\n' - '\n' - '\n' - 'XRange Type\n' - '===========\n' - '\n' - 'The "xrange" type is an immutable sequence which is commonly ' - 'used for\n' - 'looping. The advantage of the "xrange" type is that an ' - '"xrange"\n' - 'object will always take the same amount of memory, no matter the ' - 'size\n' - 'of the range it represents. There are no consistent ' - 'performance\n' - 'advantages.\n' - '\n' - 'XRange objects have very little behavior: they only support ' - 'indexing,\n' - 'iteration, and the "len()" function.\n' - '\n' - '\n' - 'Mutable Sequence Types\n' - '======================\n' - '\n' - 'List and "bytearray" objects support additional operations that ' - 'allow\n' - 'in-place modification of the object. Other mutable sequence ' - 'types\n' - '(when added to the language) should also support these ' - 'operations.\n' - 'Strings and tuples are immutable sequence types: such objects ' - 'cannot\n' - 'be modified once created. The following operations are defined ' - 'on\n' - 'mutable sequence types (where *x* is an arbitrary object):\n' - '\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| Operation | ' - 'Result | Notes |\n' - '+================================+==================================+=======================+\n' - '| "s[i] = x" | item *i* of *s* is replaced ' - 'by | |\n' - '| | ' - '*x* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s[i:j] = t" | slice of *s* from *i* to *j* ' - 'is | |\n' - '| | replaced by the contents of ' - 'the | |\n' - '| | iterable ' - '*t* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "del s[i:j]" | same as "s[i:j] = ' - '[]" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s[i:j:k] = t" | the elements of "s[i:j:k]" ' - 'are | (1) |\n' - '| | replaced by those of ' - '*t* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "del s[i:j:k]" | removes the elements ' - 'of | |\n' - '| | "s[i:j:k]" from the ' - 'list | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.append(x)" | same as "s[len(s):len(s)] = ' - '[x]" | (2) |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.extend(t)" or "s += t" | for the most part the same ' - 'as | (3) |\n' - '| | "s[len(s):len(s)] = ' - 't" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s *= n" | updates *s* with its ' - 'contents | (11) |\n' - '| | repeated *n* ' - 'times | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.count(x)" | return number of *i*\'s for ' - 'which | |\n' - '| | "s[i] == ' - 'x" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.index(x[, i[, j]])" | return smallest *k* such ' - 'that | (4) |\n' - '| | "s[k] == x" and "i <= k < ' - 'j" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.insert(i, x)" | same as "s[i:i] = ' - '[x]" | (5) |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.pop([i])" | same as "x = s[i]; del ' - 's[i]; | (6) |\n' - '| | return ' - 'x" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.remove(x)" | same as "del ' - 's[s.index(x)]" | (4) |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.reverse()" | reverses the items of *s* ' - 'in | (7) |\n' - '| | ' - 'place | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.sort([cmp[, key[, | sort the items of *s* in ' - 'place | (7)(8)(9)(10) |\n' - '| reverse]]])" ' - '| | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '\n' - 'Notes:\n' - '\n' - '1. *t* must have the same length as the slice it is replacing.\n' - '\n' - '2. The C implementation of Python has historically accepted\n' - ' multiple parameters and implicitly joined them into a tuple; ' - 'this\n' - ' no longer works in Python 2.0. Use of this misfeature has ' - 'been\n' - ' deprecated since Python 1.4.\n' - '\n' - '3. *t* can be any iterable object.\n' - '\n' - '4. Raises "ValueError" when *x* is not found in *s*. When a\n' - ' negative index is passed as the second or third parameter to ' - 'the\n' - ' "index()" method, the list length is added, as for slice ' - 'indices.\n' - ' If it is still negative, it is truncated to zero, as for ' - 'slice\n' - ' indices.\n' - '\n' - ' Changed in version 2.3: Previously, "index()" didn\'t have ' - 'arguments\n' - ' for specifying start and stop positions.\n' - '\n' - '5. When a negative index is passed as the first parameter to ' - 'the\n' - ' "insert()" method, the list length is added, as for slice ' - 'indices.\n' - ' If it is still negative, it is truncated to zero, as for ' - 'slice\n' - ' indices.\n' - '\n' - ' Changed in version 2.3: Previously, all negative indices ' - 'were\n' - ' truncated to zero.\n' - '\n' - '6. The "pop()" method\'s optional argument *i* defaults to "-1", ' - 'so\n' - ' that by default the last item is removed and returned.\n' - '\n' - '7. The "sort()" and "reverse()" methods modify the list in ' - 'place\n' - ' for economy of space when sorting or reversing a large list. ' - 'To\n' - " remind you that they operate by side effect, they don't " - 'return the\n' - ' sorted or reversed list.\n' - '\n' - '8. The "sort()" method takes optional arguments for controlling ' - 'the\n' - ' comparisons.\n' - '\n' - ' *cmp* specifies a custom comparison function of two arguments ' - '(list\n' - ' items) which should return a negative, zero or positive ' - 'number\n' - ' depending on whether the first argument is considered smaller ' - 'than,\n' - ' equal to, or larger than the second argument: "cmp=lambda ' - 'x,y:\n' - ' cmp(x.lower(), y.lower())". The default value is "None".\n' - '\n' - ' *key* specifies a function of one argument that is used to ' - 'extract\n' - ' a comparison key from each list element: "key=str.lower". ' - 'The\n' - ' default value is "None".\n' - '\n' - ' *reverse* is a boolean value. If set to "True", then the ' - 'list\n' - ' elements are sorted as if each comparison were reversed.\n' - '\n' - ' In general, the *key* and *reverse* conversion processes are ' - 'much\n' - ' faster than specifying an equivalent *cmp* function. This ' - 'is\n' - ' because *cmp* is called multiple times for each list element ' - 'while\n' - ' *key* and *reverse* touch each element only once. Use\n' - ' "functools.cmp_to_key()" to convert an old-style *cmp* ' - 'function to\n' - ' a *key* function.\n' - '\n' - ' Changed in version 2.3: Support for "None" as an equivalent ' - 'to\n' - ' omitting *cmp* was added.\n' - '\n' - ' Changed in version 2.4: Support for *key* and *reverse* was ' - 'added.\n' - '\n' - '9. Starting with Python 2.3, the "sort()" method is guaranteed ' - 'to\n' - ' be stable. A sort is stable if it guarantees not to change ' - 'the\n' - ' relative order of elements that compare equal --- this is ' - 'helpful\n' - ' for sorting in multiple passes (for example, sort by ' - 'department,\n' - ' then by salary grade).\n' - '\n' - '10. **CPython implementation detail:** While a list is being\n' - ' sorted, the effect of attempting to mutate, or even inspect, ' - 'the\n' - ' list is undefined. The C implementation of Python 2.3 and ' - 'newer\n' - ' makes the list appear empty for the duration, and raises\n' - ' "ValueError" if it can detect that the list has been ' - 'mutated\n' - ' during a sort.\n' - '\n' - '11. The value *n* is an integer, or an object implementing\n' - ' "__index__()". Zero and negative values of *n* clear the\n' - ' sequence. Items in the sequence are not copied; they are\n' - ' referenced multiple times, as explained for "s * n" under ' - 'Sequence\n' - ' Types --- str, unicode, list, tuple, bytearray, buffer, ' - 'xrange.\n', - 'typesseq-mutable': '\n' - 'Mutable Sequence Types\n' - '**********************\n' - '\n' - 'List and "bytearray" objects support additional ' - 'operations that allow\n' - 'in-place modification of the object. Other mutable ' - 'sequence types\n' - '(when added to the language) should also support these ' - 'operations.\n' - 'Strings and tuples are immutable sequence types: such ' - 'objects cannot\n' - 'be modified once created. The following operations are ' - 'defined on\n' - 'mutable sequence types (where *x* is an arbitrary ' - 'object):\n' - '\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| Operation | ' - 'Result | Notes ' - '|\n' - '+================================+==================================+=======================+\n' - '| "s[i] = x" | item *i* of *s* is ' - 'replaced by | |\n' - '| | ' - '*x* | ' - '|\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s[i:j] = t" | slice of *s* from *i* ' - 'to *j* is | |\n' - '| | replaced by the ' - 'contents of the | |\n' - '| | iterable ' - '*t* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "del s[i:j]" | same as "s[i:j] = ' - '[]" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s[i:j:k] = t" | the elements of ' - '"s[i:j:k]" are | (1) |\n' - '| | replaced by those of ' - '*t* | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "del s[i:j:k]" | removes the elements ' - 'of | |\n' - '| | "s[i:j:k]" from the ' - 'list | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.append(x)" | same as ' - '"s[len(s):len(s)] = [x]" | (2) |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.extend(t)" or "s += t" | for the most part the ' - 'same as | (3) |\n' - '| | "s[len(s):len(s)] = ' - 't" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s *= n" | updates *s* with its ' - 'contents | (11) |\n' - '| | repeated *n* ' - 'times | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.count(x)" | return number of ' - "*i*'s for which | |\n" - '| | "s[i] == ' - 'x" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.index(x[, i[, j]])" | return smallest *k* ' - 'such that | (4) |\n' - '| | "s[k] == x" and "i <= ' - 'k < j" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.insert(i, x)" | same as "s[i:i] = ' - '[x]" | (5) |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.pop([i])" | same as "x = s[i]; ' - 'del s[i]; | (6) |\n' - '| | return ' - 'x" | |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.remove(x)" | same as "del ' - 's[s.index(x)]" | (4) |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.reverse()" | reverses the items of ' - '*s* in | (7) |\n' - '| | ' - 'place | ' - '|\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '| "s.sort([cmp[, key[, | sort the items of *s* ' - 'in place | (7)(8)(9)(10) |\n' - '| reverse]]])" ' - '| ' - '| |\n' - '+--------------------------------+----------------------------------+-----------------------+\n' - '\n' - 'Notes:\n' - '\n' - '1. *t* must have the same length as the slice it is ' - 'replacing.\n' - '\n' - '2. The C implementation of Python has historically ' - 'accepted\n' - ' multiple parameters and implicitly joined them into a ' - 'tuple; this\n' - ' no longer works in Python 2.0. Use of this ' - 'misfeature has been\n' - ' deprecated since Python 1.4.\n' - '\n' - '3. *t* can be any iterable object.\n' - '\n' - '4. Raises "ValueError" when *x* is not found in *s*. ' - 'When a\n' - ' negative index is passed as the second or third ' - 'parameter to the\n' - ' "index()" method, the list length is added, as for ' - 'slice indices.\n' - ' If it is still negative, it is truncated to zero, as ' - 'for slice\n' - ' indices.\n' - '\n' - ' Changed in version 2.3: Previously, "index()" didn\'t ' - 'have arguments\n' - ' for specifying start and stop positions.\n' - '\n' - '5. When a negative index is passed as the first ' - 'parameter to the\n' - ' "insert()" method, the list length is added, as for ' - 'slice indices.\n' - ' If it is still negative, it is truncated to zero, as ' - 'for slice\n' - ' indices.\n' - '\n' - ' Changed in version 2.3: Previously, all negative ' - 'indices were\n' - ' truncated to zero.\n' - '\n' - '6. The "pop()" method\'s optional argument *i* defaults ' - 'to "-1", so\n' - ' that by default the last item is removed and ' - 'returned.\n' - '\n' - '7. The "sort()" and "reverse()" methods modify the list ' - 'in place\n' - ' for economy of space when sorting or reversing a ' - 'large list. To\n' - ' remind you that they operate by side effect, they ' - "don't return the\n" - ' sorted or reversed list.\n' - '\n' - '8. The "sort()" method takes optional arguments for ' - 'controlling the\n' - ' comparisons.\n' - '\n' - ' *cmp* specifies a custom comparison function of two ' - 'arguments (list\n' - ' items) which should return a negative, zero or ' - 'positive number\n' - ' depending on whether the first argument is considered ' - 'smaller than,\n' - ' equal to, or larger than the second argument: ' - '"cmp=lambda x,y:\n' - ' cmp(x.lower(), y.lower())". The default value is ' - '"None".\n' - '\n' - ' *key* specifies a function of one argument that is ' - 'used to extract\n' - ' a comparison key from each list element: ' - '"key=str.lower". The\n' - ' default value is "None".\n' - '\n' - ' *reverse* is a boolean value. If set to "True", then ' - 'the list\n' - ' elements are sorted as if each comparison were ' - 'reversed.\n' - '\n' - ' In general, the *key* and *reverse* conversion ' - 'processes are much\n' - ' faster than specifying an equivalent *cmp* function. ' - 'This is\n' - ' because *cmp* is called multiple times for each list ' - 'element while\n' - ' *key* and *reverse* touch each element only once. ' - 'Use\n' - ' "functools.cmp_to_key()" to convert an old-style ' - '*cmp* function to\n' - ' a *key* function.\n' - '\n' - ' Changed in version 2.3: Support for "None" as an ' - 'equivalent to\n' - ' omitting *cmp* was added.\n' - '\n' - ' Changed in version 2.4: Support for *key* and ' - '*reverse* was added.\n' - '\n' - '9. Starting with Python 2.3, the "sort()" method is ' - 'guaranteed to\n' - ' be stable. A sort is stable if it guarantees not to ' - 'change the\n' - ' relative order of elements that compare equal --- ' - 'this is helpful\n' - ' for sorting in multiple passes (for example, sort by ' - 'department,\n' - ' then by salary grade).\n' - '\n' - '10. **CPython implementation detail:** While a list is ' - 'being\n' - ' sorted, the effect of attempting to mutate, or even ' - 'inspect, the\n' - ' list is undefined. The C implementation of Python ' - '2.3 and newer\n' - ' makes the list appear empty for the duration, and ' - 'raises\n' - ' "ValueError" if it can detect that the list has been ' - 'mutated\n' - ' during a sort.\n' - '\n' - '11. The value *n* is an integer, or an object ' - 'implementing\n' - ' "__index__()". Zero and negative values of *n* ' - 'clear the\n' - ' sequence. Items in the sequence are not copied; ' - 'they are\n' - ' referenced multiple times, as explained for "s * n" ' - 'under Sequence\n' - ' Types --- str, unicode, list, tuple, bytearray, ' - 'buffer, xrange.\n', - 'unary': '\n' - 'Unary arithmetic and bitwise operations\n' - '***************************************\n' - '\n' - 'All unary arithmetic and bitwise operations have the same ' - 'priority:\n' - '\n' - ' u_expr ::= power | "-" u_expr | "+" u_expr | "~" u_expr\n' - '\n' - 'The unary "-" (minus) operator yields the negation of its numeric\n' - 'argument.\n' - '\n' - 'The unary "+" (plus) operator yields its numeric argument ' - 'unchanged.\n' - '\n' - 'The unary "~" (invert) operator yields the bitwise inversion of ' - 'its\n' - 'plain or long integer argument. The bitwise inversion of "x" is\n' - 'defined as "-(x+1)". It only applies to integral numbers.\n' - '\n' - 'In all three cases, if the argument does not have the proper type, ' - 'a\n' - '"TypeError" exception is raised.\n', - 'while': '\n' - 'The "while" statement\n' - '*********************\n' - '\n' - 'The "while" statement is used for repeated execution as long as an\n' - 'expression is true:\n' - '\n' - ' while_stmt ::= "while" expression ":" suite\n' - ' ["else" ":" suite]\n' - '\n' - 'This repeatedly tests the expression and, if it is true, executes ' - 'the\n' - 'first suite; if the expression is false (which may be the first ' - 'time\n' - 'it is tested) the suite of the "else" clause, if present, is ' - 'executed\n' - 'and the loop terminates.\n' - '\n' - 'A "break" statement executed in the first suite terminates the ' - 'loop\n' - 'without executing the "else" clause\'s suite. A "continue" ' - 'statement\n' - 'executed in the first suite skips the rest of the suite and goes ' - 'back\n' - 'to testing the expression.\n', - 'with': '\n' - 'The "with" statement\n' - '********************\n' - '\n' - 'New in version 2.5.\n' - '\n' - 'The "with" statement is used to wrap the execution of a block with\n' - 'methods defined by a context manager (see section With Statement\n' - 'Context Managers). This allows common "try"..."except"..."finally"\n' - 'usage patterns to be encapsulated for convenient reuse.\n' - '\n' - ' with_stmt ::= "with" with_item ("," with_item)* ":" suite\n' - ' with_item ::= expression ["as" target]\n' - '\n' - 'The execution of the "with" statement with one "item" proceeds as\n' - 'follows:\n' - '\n' - '1. The context expression (the expression given in the "with_item")\n' - ' is evaluated to obtain a context manager.\n' - '\n' - '2. The context manager\'s "__exit__()" is loaded for later use.\n' - '\n' - '3. The context manager\'s "__enter__()" method is invoked.\n' - '\n' - '4. If a target was included in the "with" statement, the return\n' - ' value from "__enter__()" is assigned to it.\n' - '\n' - ' Note: The "with" statement guarantees that if the "__enter__()"\n' - ' method returns without an error, then "__exit__()" will always ' - 'be\n' - ' called. Thus, if an error occurs during the assignment to the\n' - ' target list, it will be treated the same as an error occurring\n' - ' within the suite would be. See step 6 below.\n' - '\n' - '5. The suite is executed.\n' - '\n' - '6. The context manager\'s "__exit__()" method is invoked. If an\n' - ' exception caused the suite to be exited, its type, value, and\n' - ' traceback are passed as arguments to "__exit__()". Otherwise, ' - 'three\n' - ' "None" arguments are supplied.\n' - '\n' - ' If the suite was exited due to an exception, and the return ' - 'value\n' - ' from the "__exit__()" method was false, the exception is ' - 'reraised.\n' - ' If the return value was true, the exception is suppressed, and\n' - ' execution continues with the statement following the "with"\n' - ' statement.\n' - '\n' - ' If the suite was exited for any reason other than an exception, ' - 'the\n' - ' return value from "__exit__()" is ignored, and execution ' - 'proceeds\n' - ' at the normal location for the kind of exit that was taken.\n' - '\n' - 'With more than one item, the context managers are processed as if\n' - 'multiple "with" statements were nested:\n' - '\n' - ' with A() as a, B() as b:\n' - ' suite\n' - '\n' - 'is equivalent to\n' - '\n' - ' with A() as a:\n' - ' with B() as b:\n' - ' suite\n' - '\n' - 'Note: In Python 2.5, the "with" statement is only allowed when the\n' - ' "with_statement" feature has been enabled. It is always enabled ' - 'in\n' - ' Python 2.6.\n' - '\n' - 'Changed in version 2.7: Support for multiple context expressions.\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 343** - The "with" statement\n' - ' The specification, background, and examples for the Python ' - '"with"\n' - ' statement.\n', - 'yield': '\n' - 'The "yield" statement\n' - '*********************\n' - '\n' - ' yield_stmt ::= yield_expression\n' - '\n' - 'The "yield" statement is only used when defining a generator ' - 'function,\n' - 'and is only used in the body of the generator function. Using a\n' - '"yield" statement in a function definition is sufficient to cause ' - 'that\n' - 'definition to create a generator function instead of a normal\n' - 'function.\n' - '\n' - 'When a generator function is called, it returns an iterator known ' - 'as a\n' - 'generator iterator, or more commonly, a generator. The body of ' - 'the\n' - "generator function is executed by calling the generator's " - '"next()"\n' - 'method repeatedly until it raises an exception.\n' - '\n' - 'When a "yield" statement is executed, the state of the generator ' - 'is\n' - 'frozen and the value of "expression_list" is returned to ' - '"next()"\'s\n' - 'caller. By "frozen" we mean that all local state is retained,\n' - 'including the current bindings of local variables, the instruction\n' - 'pointer, and the internal evaluation stack: enough information is\n' - 'saved so that the next time "next()" is invoked, the function can\n' - 'proceed exactly as if the "yield" statement were just another ' - 'external\n' - 'call.\n' - '\n' - 'As of Python version 2.5, the "yield" statement is now allowed in ' - 'the\n' - '"try" clause of a "try" ... "finally" construct. If the generator ' - 'is\n' - 'not resumed before it is finalized (by reaching a zero reference ' - 'count\n' - "or by being garbage collected), the generator-iterator's " - '"close()"\n' - 'method will be called, allowing any pending "finally" clauses to\n' - 'execute.\n' - '\n' - 'For full details of "yield" semantics, refer to the Yield ' - 'expressions\n' - 'section.\n' - '\n' - 'Note: In Python 2.2, the "yield" statement was only allowed when ' - 'the\n' - ' "generators" feature has been enabled. This "__future__" import\n' - ' statement was used to enable the feature:\n' - '\n' - ' from __future__ import generators\n' - '\n' - 'See also:\n' - '\n' - ' **PEP 255** - Simple Generators\n' - ' The proposal for adding generators and the "yield" statement ' - 'to\n' - ' Python.\n' - '\n' - ' **PEP 342** - Coroutines via Enhanced Generators\n' - ' The proposal that, among other generator enhancements, ' - 'proposed\n' - ' allowing "yield" to appear inside a "try" ... "finally" ' - 'block.\n'} |