types --- 動態型別建立與內建型別名稱¶原始碼：Lib/types.py
This module defines utility functions 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 int or
str are.
Finally, it provides some additional type-related utility classes and functions that are not fundamental enough to be builtins.
Creates a class object dynamically using the appropriate metaclass.
The first three arguments are the components that make up a class
definition header: the class name, the base classes (in order), the
keyword arguments (such as metaclass).
The exec_body argument is a callback that is used to populate the
freshly created class namespace. It should accept the class namespace
as its sole argument and update the namespace directly with the class
contents. If no callback is provided, it has the same effect as passing
in lambda ns: None.
在 3.3 版被加入.
Calculates the appropriate metaclass and creates the class namespace.
The arguments are the components that make up a class definition header:
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 and 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.
在 3.3 版被加入.
在 3.6 版的變更: The default value for the namespace element of the returned
tuple has changed. Now an insertion-order-preserving mapping is
used when the metaclass does not have a __prepare__ method.
也參考
Full details of the class creation process supported by these functions
Introduced the __prepare__ namespace hook
Resolve MRO entries dynamically as specified by PEP 560.
This function looks for items in bases that are not instances of
type, and returns a tuple where each such object that has
an __mro_entries__() method is replaced with an unpacked result of
calling this method. If a bases item is an instance of type,
or it doesn't have an __mro_entries__() method, then it is included in
the return tuple unchanged.
在 3.7 版被加入.
Return the tuple of objects originally given as the bases of cls before
the __mro_entries__() method has been called on any bases
(following the mechanisms laid out in PEP 560). This is useful for
introspecting Generics.
For classes that have an __orig_bases__ attribute, this
function returns the value of cls.__orig_bases__.
For classes without the __orig_bases__ attribute,
cls.__bases__ is returned.
舉例來說：
from typing import TypeVar, Generic, NamedTuple, TypedDict
T = TypeVar("T")
class Foo(Generic[T]): ...
class Bar(Foo[int], float): ...
class Baz(list[str]): ...
Eggs = NamedTuple("Eggs", [("a", int), ("b", str)])
Spam = TypedDict("Spam", {"a": int, "b": str})
assert Bar.__bases__ == (Foo, float)
assert get_original_bases(Bar) == (Foo[int], float)
assert Baz.__bases__ == (list,)
assert get_original_bases(Baz) == (list[str],)
assert Eggs.__bases__ == (tuple,)
assert get_original_bases(Eggs) == (NamedTuple,)
assert Spam.__bases__ == (dict,)
assert get_original_bases(Spam) == (TypedDict,)
assert int.__bases__ == (object,)
assert get_original_bases(int) == (object,)
在 3.12 版被加入.
也參考
PEP 560 - Core support for typing module and generic 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 of these names is for isinstance() or
issubclass() checks.
If you instantiate any of these types, note that signatures may vary between Python versions.
Standard names are defined for the following types:
The type of user-defined functions and functions created by
lambda expressions.
引發一個附帶引數 code 的稽核事件 function.__new__。
The audit event only occurs for direct instantiation of function objects, and is not raised for normal compilation.
The type of asynchronous generator-iterator objects, created by asynchronous generator functions.
在 3.6 版被加入.
The type of code objects such as returned by compile().
引發一個附帶引數 code、filename、name、argcount、posonlyargcount、kwonlyargcount、nlocals、stacksize、flags 的稽核事件 code.__new__。
Note that the audited arguments may not match the names or positions required by the initializer. The audit event only occurs for direct instantiation of code objects, and is not raised for normal compilation.
The type for cell objects: such objects are used as containers for a function's closure variables.
在 3.8 版被加入.
The type of methods of user-defined class instances.
The type of built-in functions like len() or sys.exit(), and
methods of built-in classes. (Here, the term "built-in" means "written in
C".)
The type of methods of some built-in data types and base classes such as
object.__init__() or object.__lt__().
在 3.7 版被加入.
The type of bound methods of some built-in data types and base classes.
For example it is the type of object().__str__.
在 3.7 版被加入.
The type of NotImplemented.
在 3.10 版被加入.
The type of methods of some built-in data types such as str.join().
在 3.7 版被加入.
The type of unbound class methods of some built-in data types such as
dict.__dict__['fromkeys'].
在 3.7 版被加入.
The type of modules. The constructor takes the name of the module to be created and optionally its docstring.
也參考
Provides details on the special attributes that can be found on
instances of ModuleType.
importlib.util.module_from_spec()Modules created using the ModuleType constructor are
created with many of their special attributes unset or set to default
values. module_from_spec() provides a more robust way of
creating ModuleType instances which ensures the various
attributes are set appropriately.
The type of parameterized generics such as
list[int].
t_origin should be a non-parameterized generic class, such as list,
tuple or dict. t_args should be a tuple (possibly of
length 1) of types which parameterize t_origin:
>>> from types import GenericAlias
>>> list[int] == GenericAlias(list, (int,))
True
>>> dict[str, int] == GenericAlias(dict, (str, int))
True
在 3.9 版被加入.
在 3.9.2 版的變更: This type can now be subclassed.
也參考
In-depth documentation on instances of types.GenericAlias
Introducing the types.GenericAlias class
The type of union type expressions.
在 3.10 版被加入.
The type of traceback objects such as found in sys.exception().__traceback__.
See the language reference for details of the available attributes and operations, and guidance on creating tracebacks dynamically.
The type of frame objects such as found in
tb.tb_frame if tb is a traceback object.
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
property type, but for classes defined in extension modules.
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 property type, but for classes defined in extension modules.
In addition, when a class is defined with a __slots__ attribute, then for
each slot, an instance of MemberDescriptorType will be added as an attribute
on the class. This allows the slot to appear in the class's __dict__.
CPython 實作細節： In other implementations of Python, this type may be identical to
GetSetDescriptorType.
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.
在 3.3 版被加入.
在 3.9 版的變更: Updated to support the new union (|) operator from PEP 584, which
simply delegates to the underlying mapping.
Return True if the underlying mapping has a key key, else
False.
Return the item of the underlying mapping with key key. Raises a
KeyError if key is not in the underlying mapping.
Return an iterator over the keys of the underlying mapping. This is a
shortcut for iter(proxy.keys()).
Return the number of items in the underlying mapping.
Return a shallow copy of the underlying mapping.
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 KeyError.
Return a new view of the underlying mapping's items ((key, value)
pairs).
Return a new view of the underlying mapping's keys.
Return a new view of the underlying mapping's values.
Return a reverse iterator over the keys of the underlying mapping.
在 3.9 版被加入.
Return a hash of the underlying mapping.
在 3.12 版被加入.
The type of capsule objects.
在 3.13 版被加入.
A simple object subclass that provides attribute access to its
namespace, as well as a meaningful repr.
Unlike object, with SimpleNamespace you can add and remove
attributes.
SimpleNamespace objects may be initialized
in the same way as dict: either with keyword arguments,
with a single positional argument, or with both.
When initialized with keyword arguments,
those are directly added to the underlying namespace.
Alternatively, when initialized with a positional argument,
the underlying namespace will be updated with key-value pairs
from that argument (either a mapping object or
an iterable object producing key-value pairs).
All such keys must be strings.
The type is roughly equivalent to the following code:
class SimpleNamespace:
def __init__(self, mapping_or_iterable=(), /, **kwargs):
self.__dict__.update(mapping_or_iterable)
self.__dict__.update(kwargs)
def __repr__(self):
items = (f"{k}={v!r}" for k, v in self.__dict__.items())
return "{}({})".format(type(self).__name__, ", ".join(items))
def __eq__(self, other):
if isinstance(self, SimpleNamespace) and isinstance(other, SimpleNamespace):
return self.__dict__ == other.__dict__
return NotImplemented
SimpleNamespace may be useful as a replacement for class NS: pass.
However, for a structured record type use namedtuple()
instead.
SimpleNamespace objects are supported by copy.replace().
在 3.3 版被加入.
在 3.9 版的變更: Attribute order in the repr changed from alphabetical to insertion (like
dict).
在 3.13 版的變更: Added support for an optional positional argument.
Route attribute access on a class to __getattr__.
This is a descriptor, used to define attributes that act differently when accessed through an instance and through a class. Instance access remains normal, but access to an attribute through a class will be routed to the class's __getattr__ method; this is done by raising AttributeError.
This allows one to have properties active on an instance, and have virtual
attributes on the class with the same name (see enum.Enum for an example).
在 3.4 版被加入.
This function transforms a generator function into a
coroutine function which returns a generator-based coroutine.
The generator-based coroutine is still a generator iterator,
but is also considered to be a coroutine object and is
awaitable. However, it may not necessarily implement
the __await__() method.
If gen_func is a generator function, it will be modified in-place.
If gen_func is not a generator function, it will be wrapped. If it
returns an instance of collections.abc.Generator, the instance
will be wrapped in an awaitable proxy object. All other types
of objects will be returned as is.
在 3.5 版被加入.