`types` --- 動態型別建立與內建型別名稱¶

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.

Dynamic Type Creation¶

types.new_class(name, bases=(), kwds=None, exec_body=None)¶

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.

types.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 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

Metaclasses: Full details of the class creation process supported by these functions
PEP 3115 - Metaclasses in Python 3000: Introduced the __prepare__ namespace hook

types.resolve_bases(bases)¶

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.

types.get_original_bases(cls, /)¶

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

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 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:

types.NoneType¶: The type of None.

在 3.10 版被加入.

types.FunctionType¶

types.LambdaType¶

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.

types.GeneratorType¶: The type of generator-iterator objects, created by generator functions.

types.CoroutineType¶: The type of coroutine objects, created by async def functions.

在 3.5 版被加入.

types.AsyncGeneratorType¶: The type of asynchronous generator-iterator objects, created by asynchronous generator functions.

在 3.6 版被加入.

class types.CodeType(**kwargs)¶

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.

types.CellType¶: The type for cell objects: such objects are used as containers for a function's closure variables.

在 3.8 版被加入.

types.MethodType¶: The type of methods of user-defined class instances.

types.BuiltinFunctionType¶
types.BuiltinMethodType¶: 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".)

types.WrapperDescriptorType¶: 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.

types.MethodWrapperType¶: 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.

types.NotImplementedType¶: The type of NotImplemented.

在 3.10 版被加入.

types.MethodDescriptorType¶: The type of methods of some built-in data types such as str.join().

在 3.7 版被加入.

types.ClassMethodDescriptorType¶: The type of unbound class methods of some built-in data types such as dict.__dict__['fromkeys'].

在 3.7 版被加入.

class types.ModuleType(name, doc=None)¶

The type of modules. The constructor takes the name of the module to be created and optionally its docstring.

也參考

模組物件的文件: 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.

types.EllipsisType¶: The type of Ellipsis.

在 3.10 版被加入.

class types.GenericAlias(t_origin, t_args)¶

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

types --- 動態型別建立與內建型別名稱¶

Dynamic Type Creation¶

Standard Interpreter Types¶

`types` --- 動態型別建立與內建型別名稱¶