11.3. copy_reg — 注册 pickle 支持函数 ¶

注意

The copy_reg module has been renamed to copyreg in Python 3. The 2to3 tool will automatically adapt imports when converting your sources to Python 3.

The copy_reg module offers a way to define fuctions used while pickling specific objects. The pickle , cPickle ，和 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)。

copy_reg. 构造函数 ( object ) ¶

声明 object 成为有效构造函数。若 object 不可调用 (因此作为构造函数无效)，引发 TypeError .

copy_reg. pickle ( type , function [ , 构造函数 ] ) ¶

声明 function should be used as a “reduction” function for objects of type type ; type must not be a “classic” class object. (Classic classes are handled differently; see the documentation for the pickle module for details.) 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 不可调用。

见 pickle module for more details on the interface expected of function and 构造函数 .

>>> import copy_reg, 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,)
...
>>> copy_reg.pickle(C, pickle_c)
>>> c = C(1)
>>> d = copy.copy(c)
pickling a C instance...
>>> p = pickle.dumps(c)
pickling a C instance...