Pickling in Python

title: Pickling in Python


Pickling refers to the serialization and deserialization of an object in Python. It essentially stores an object to a file so the user can load it later on. During pickling, the Python object is converted to a binary stream.

Usage Example

First let’s create a class:

class ExampleClass(): def __init__(self, integer, string, number_list): self.integer = integer self.string = string self.number_list = number_list def print_attributes(self): print(self.integer, self.string, self.number_list) def print_sum(self): print(sum(self.number_list)) instance = ExampleClass(10, 'rubberducky', [1, 2, 3, 1, 2]) instance.print_attributes() # Prints 10 rubberducky [1, 2, 3, 1, 2] instance.print_sum() # Prints 9


Now, let’s try pickling it:

import pickle with open('file.pickle', 'wb') as file: pickle.dump(instance, file)

This creates the file file.pickle. According to this StackOverflow thread, Python 3’s preferred extension is .pickle. Now we simply need to lead it:

import pickle with open('file.pickle', 'rb') as file: loaded = pickle.load(file) loaded.print_attributes() # Prints 10 rubberducky [1, 2, 3, 1, 2] loaded.print_sum() # Prints 9

It works! Note that both times, open()‘s mode was rb or wb, as opposed to the regular r or w (which stand for read and write). This is because of how pickle works: it uses binary.

More Information

Python – Pickling

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