copyreg
— 注册
pickle
支持函数
¶
源代码： Lib/copyreg.py
copyreg
模块提供腌制特定对象时，定义使用函数的方式。
pickle
and
copy
模块使用这些函数，当腌制/拷贝这些对象时。模块提供有关对象构造函数 (不是类) 的配置信息。这种构造函数可以是工厂函数 (或类实例)。
copyreg.
pickle
(
type
,
function
,
constructor=None
)
¶
声明 function should be used as a “reduction” function for objects of type type . function should return either a string or a tuple containing two or three elements.
可选
构造函数
parameter, if provided, is a callable object which can be used to reconstruct the object when called with the tuple of arguments returned by
function
at pickling time.
TypeError
会被引发若
object
is a class or
构造函数
is not callable.
见
pickle
module for more details on the interface expected of
function
and
构造函数
。注意，
dispatch_table
attribute of a pickler object or subclass of
pickle.Pickler
can also be used for declaring reduction functions.
以下范例愿意展示如何注册 pickle 函数及如何使用它：
>>> import copyreg, copy, pickle
>>> class C(object):
... def __init__(self, a):
... self.a = a
...
>>> def pickle_c(c):
... print("pickling a C instance...")
... return C, (c.a,)
...
>>> copyreg.pickle(C, pickle_c)
>>> c = C(1)
>>> d = copy.copy(c)
pickling a C instance...
>>> p = pickle.dumps(c)
pickling a C instance...