1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
|
:mod:`types` --- Dynamic type creation and names for built-in types
===================================================================
.. module:: types
:synopsis: Names for built-in types.
**Source code:** :source:`Lib/types.py`
--------------
This module defines utility function to assist in dynamic creation of
new types.
It also defines names for some object types that are used by the standard
Python interpreter, but not exposed as builtins like :class:`int` or
:class:`str` are.
Dynamic Type Creation
---------------------
.. function:: new_class(name, bases=(), kwds=None, exec_body=None)
Creates a class object dynamically using the appropriate metaclass.
The arguments are the components that make up a class definition: the
class name, the base classes (in order), the keyword arguments (such as
``metaclass``) and the callback function to populate the class namespace.
The *exec_body* callback should accept the class namespace as its sole
argument and update the namespace directly with the class contents.
.. function:: prepare_class(name, bases=(), kwds=None)
Calculates the appropriate metaclass and creates the class namespace.
The arguments are the components that make up a class definition: the
class name, the base classes (in order) and the keyword arguments (such as
``metaclass``).
The return value is a 3-tuple: ``metaclass, namespace, kwds``
*metaclass* is the appropriate metaclass
*namespace* is the prepared class namespace
*kwds* is an updated copy of the passed in *kwds* argument with any
``'metaclass'`` entry removed. If no *kwds* argument is passed in, this
will be an empty dict.
.. seealso::
:pep:`3115` - Metaclasses in Python 3000
Introduced the ``__prepare__`` namespace hook
Standard Interpreter Types
--------------------------
This module provides names for many of the types that are required to
implement a Python interpreter. It deliberately avoids including some of
the types that arise only incidentally during processing such as the
``listiterator`` type.
Typical use is of these names is for :func:`isinstance` or
:func:`issubclass` checks.
Standard names are defined for the following types:
.. data:: FunctionType
LambdaType
The type of user-defined functions and functions created by
:keyword:`lambda` expressions.
.. data:: GeneratorType
The type of :term:`generator`-iterator objects, produced by calling a
generator function.
.. data:: CodeType
.. index:: builtin: compile
The type for code objects such as returned by :func:`compile`.
.. data:: MethodType
The type of methods of user-defined class instances.
.. data:: BuiltinFunctionType
BuiltinMethodType
The type of built-in functions like :func:`len` or :func:`sys.exit`, and
methods of built-in classes. (Here, the term "built-in" means "written in
C".)
.. data:: ModuleType
The type of modules.
.. data:: TracebackType
The type of traceback objects such as found in ``sys.exc_info()[2]``.
.. data:: FrameType
The type of frame objects such as found in ``tb.tb_frame`` if ``tb`` is a
traceback object.
.. data:: GetSetDescriptorType
The type of objects defined in extension modules with ``PyGetSetDef``, such
as ``FrameType.f_locals`` or ``array.array.typecode``. This type is used as
descriptor for object attributes; it has the same purpose as the
:class:`property` type, but for classes defined in extension modules.
.. data:: MemberDescriptorType
The type of objects defined in extension modules with ``PyMemberDef``, such
as ``datetime.timedelta.days``. This type is used as descriptor for simple C
data members which use standard conversion functions; it has the same purpose
as the :class:`property` type, but for classes defined in extension modules.
.. impl-detail::
In other implementations of Python, this type may be identical to
``GetSetDescriptorType``.
.. class:: MappingProxyType(mapping)
Read-only proxy of a mapping. It provides a dynamic view on the mapping's
entries, which means that when the mapping changes, the view reflects these
changes.
.. versionadded:: 3.3
.. describe:: key in proxy
Return ``True`` if the underlying mapping has a key *key*, else
``False``.
.. describe:: proxy[key]
Return the item of the underlying mapping with key *key*. Raises a
:exc:`KeyError` if *key* is not in the underlying mapping.
.. describe:: iter(proxy)
Return an iterator over the keys of the underlying mapping. This is a
shortcut for ``iter(proxy.keys())``.
.. describe:: len(proxy)
Return the number of items in the underlying mapping.
.. method:: copy()
Return a shallow copy of the underlying mapping.
.. method:: get(key[, default])
Return the value for *key* if *key* is in the underlying mapping, else
*default*. If *default* is not given, it defaults to ``None``, so that
this method never raises a :exc:`KeyError`.
.. method:: items()
Return a new view of the underlying mapping's items (``(key, value)``
pairs).
.. method:: keys()
Return a new view of the underlying mapping's keys.
.. method:: values()
Return a new view of the underlying mapping's values.
|
