Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
What are Pickling and Unpickling in Python?
To serialize and de-serialize a Python object structure, we have the Pickle module in Python. The pickle module implements binary protocols for serializing and de-serializing a Python object structure.
Pickling is the process through which a Python object hierarchy is converted into a byte stream. To serialize an object hierarchy, you simply call the dumps() function.
Unpickling is the inverse operation. A byte stream from a binary file or bytes-like object is converted back into an object hierarchy. To de-serialize a data stream, you call the loads() function.
Pickling and unpickling are alternatively known as serialization.
What can be pickled and unpickled?
In Python, the following types can be pickled −
- None, True, and False.
- integers, floating-point numbers, complex numbers.
- strings, bytes, bytearrays.
- tuples, lists, sets, and dictionaries containing only picklable objects.
- functions, built-in and user-defined.
Pickle Module Constants
The following are the constants provided by the pickle module −
pickle.HIGHEST_PROTOCOL − The highest protocol version available. Integer value.
pickle.DEFAULT_PROTOCOL − The default protocol version used for pickling. Integer value. Currently the default protocol is 4
Pickle Module Functions
The following are the functions provided by the pickle module −
pickle.dump() − Write the pickled representation of the object to the open file object file.
pickle.dumps() − Return the pickled representation of the object as a bytes object, instead of writing it to a file.
pickle.load() − Read the pickled representation of an object from the open file object file.
pickle.loads() − Return the reconstituted object hierarchy of the pickled representation data of an object
Example
First, the pickle module is imported −
import pickle
We have created the following input to be pickled.
my_data = { 'BMW', 'Audi', 'Toyota', 'Benz'}
The demo.pickle file is created. This same .pickle file is pickled with the above list
with open("demo.pickle","wb") as file_handle: pickle.dump(my_data, file_handle, pickle.HIGHEST_PROTOCOL)
Now, unpickle the above pickled file and get the input values back.
with open("demo.pickle","rb") as file_handle: res = pickle.load(file_handle) print(res_data)
Let us now see the complete example
import pickle # Input Data my_data = { 'BMW', 'Audi', 'Toyota', 'Benz'} # Pickle the input with open("demo.pickle","wb") as file_handle: pickle.dump(my_data, file_handle, pickle.HIGHEST_PROTOCOL) # Unpickle the above pickled file with open("demo.pickle","rb") as file_handle: res = pickle.load(file_handle) print(my_data) # display the output
Output
{'Benz', 'Toyota', 'Audi', 'BMW'}
6K+ Views
