Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

copyreg — Register pickle support functions

  • Difficulty Level : Medium
  • Last Updated : 08 Dec, 2020

The copyreg module defines functions which are used by pickling specific objects while pickling or copying. This module provides configuration information about object constructors(may be factory functions or class instances) which are not classes.

copyreg.constructor(object)
This function is used for declaring object as a valid constructor. An object is not considered as a valid constructor if it is not callable. This function raises TypeError if the object is not callable.

 Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.  

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning - Basic Level Course

copyreg.pickle(type, function, constructor=None)
This is used to declare function as a “reduction” function for objects of type type. function should return either a string or a tuple containing two or three elements.
The constructor parameter is optional. It 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 is raised if object is a class or constructor is not callable.



Example :




# Python 3 program to illustrate 
# use of copyreg module 
import copyreg, copy, pickle 
  
class B(object): 
    def __init__(self, a): 
        self.a =
  
def pickle_b(b): 
    print("pickling a C instance..."
    return C, (b.a, ) 
  
copyreg.pickle(B, pickle_b) 
b = B(1
d = copy.copy(b) 
print (d) 
  
r = pickle.dumps(b) 
print (r) 

Output :

pickling a C instance...

pickling a C instance...
b'\x80\x03c__main__\nC\nq\x00K\x01\x85q\x01Rq\x02.'

This article is contributed by Aditi Gupta. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!