types
— 动态类型的创建和内置类型的名称
¶
源代码： Lib/types.py
This module defines utility function to assist in dynamic creation of new types.
它还定义用于标准 Python 解释器的一些对象类型的名称，但未暴露作为内置像
int
or
str
are.
最后，它提供了一些不够基础内置的额外类型相关实用类和函数。
类型。
new_class
(
name
,
bases=()
,
kwds=None
,
exec_body=None
)
¶
使用适当元类动态创建类对象。
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: ns
.
3.3 版新增。
类型。
prepare_class
(
name
,
bases=()
,
kwds=None
)
¶
计算适当元类并创建类名称空间。
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
).
返回值是 3 元组：
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.
3.3 版新增。
另请参阅
此模块为实现 Python 解释器要求的许多类型提供名称。它故意避免包括在处理期间偶然出现的一些类型，譬如
listiterator
类型。
这些名称的典型用法是进行
isinstance()
or
issubclass()
校验。
下列类型是定义的标准名称：
类型。
MethodType
¶
用户定义类实例方法的类型。
类型。
BuiltinFunctionType
¶
类型。
BuiltinMethodType
¶
内置函数的类型像
len()
or
sys.exit()
, and methods of built-in classes. (Here, the term “built-in” means “written in C”.)
类型。
ModuleType
(
name
,
doc=None
)
¶
类型对于 模块 . Constructor takes the name of the module to be created and optionally its docstring .
注意
使用
importlib.util.module_from_spec()
to create a new module if you wish to set the various import-controlled attributes.
__name__
¶
The name of the module.
__package__
¶
Which
包
a module belongs to. If the module is top-level (i.e. not a part of any specific package) then the attribute should be set to
''
, else it should be set to the name of the package (which can be
__name__
if the module is a package itself). Defaults to
None
.
3.4 版改变：
默认为
None
。先前，属性是可选的。
类型。
TracebackType
¶
The type of traceback objects such as found in
sys.exc_info()[2]
.
类型。
FrameType
¶
The type of frame objects such as found in
tb.tb_frame
if
tb
is a traceback object.
类型。
GetSetDescriptorType
¶
The type of objects defined in extension modules with
PyGetSetDef
，譬如
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.
类型。
MemberDescriptorType
¶
The type of objects defined in extension modules with
PyMemberDef
，譬如
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.
CPython 实现细节：
In other implementations of Python, this type may be identical to
GetSetDescriptorType
.
类型。
MappingProxyType
(
映射
)
¶
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.
3.3 版新增。
key in proxy
返回
True
if the underlying mapping has a key
key
，否则
False
.
proxy[key]
Return the item of the underlying mapping with key
key
。引发
KeyError
if
key
is not in the underlying mapping.
iter(proxy)
Return an iterator over the keys of the underlying mapping. This is a shortcut for
iter(proxy.keys())
.
len(proxy)
Return the number of items in the underlying mapping.
copy
(
)
¶
返回底层映射的浅拷贝。
get
(
key
[
,
default
]
)
¶
返回值为
key
if
key
is in the underlying mapping, else
default
。若
default
不给定，默认为
None
，因此此方法从不引发
KeyError
.
项
(
)
¶
Return a new view of the underlying mapping’s items (
(key, value)
对)。
keys
(
)
¶
Return a new view of the underlying mapping’s keys.
值
(
)
¶
Return a new view of the underlying mapping’s values.
类型。
SimpleNamespace
¶
简单
object
subclass that provides attribute access to its namespace, as well as a meaningful repr.
不像
object
，采用
SimpleNamespace
you can add and remove attributes. If a
SimpleNamespace
object is initialized with keyword arguments, those are directly added to the underlying namespace.
The type is roughly equivalent to the following code:
class SimpleNamespace: def __init__(self, **kwargs): self.__dict__.update(kwargs) def __repr__(self): keys = sorted(self.__dict__) items = ("{}={!r}".format(k, self.__dict__[k]) for k in keys) return "{}({})".format(type(self).__name__, ", ".join(items)) def __eq__(self, other): return self.__dict__ == other.__dict__
SimpleNamespace
may be useful as a replacement for
class NS: pass
. However, for a structured record type use
namedtuple()
代替。
3.3 版新增。
类型。
DynamicClassAttribute
(
fget=None
,
fset=None
,
fdel=None
,
doc=None
)
¶
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 for an example).
3.4 版新增。
类型。
协程
(
gen_func
)
¶
此函数变换
generator
函数成
协程函数
返回基于生成器的协程。基于生成器的协程仍是
生成器迭代器
，但也被认为是
协程
对象和
awaitable
。不管怎样，它可能不必实现
__await__()
方法。
若 gen_func 是生成器函数，它将被原位修改。
若
gen_func
不是生成器函数，它会被包裹。若它返回实例化
collections.abc.Generator
，实例将包裹在
awaitable
代理对象。所有其它类型对象将按原样返回。
3.5 版新增。