12.2. copyreg — Register pickle support functions - Python 3.6.15 documentation 编辑
Source code: Lib/copyreg.py
The copyreg
module offers a way to define functions used while pickling specific objects. The pickle
and copy
modules use those functions when pickling/copying those objects. The module provides configuration information about object constructors which are not classes. Such constructors may be factory functions or class instances.
copyreg.
constructor
(object)Declares object to be a valid constructor. If object is not callable (and hence not valid as a constructor), raises
TypeError
.
copyreg.
pickle
(type, function, constructor=None)Declares that 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.
The optional constructor 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
will be raised if object is a class or constructor is not callable.See the
pickle
module for more details on the interface expected of function and constructor. Note that thedispatch_table
attribute of a pickler object or subclass ofpickle.Pickler
can also be used for declaring reduction functions.
12.2.1. Example
The example below would like to show how to register a pickle function and how it will be used:
>>> 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...
如果你对这篇内容有疑问,欢迎到本站社区发帖提问 参与讨论,获取更多帮助,或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱,如果其他用户或者作者回复了您的评论,将不能在第一时间通知您!
发布评论