What is pickling and unpickling?

Pickling

It is a process of converting a object into a bytes stream and it is bstored into a file.

Unpickling

It is inverse operation of pickling. Unpickling is a process where a byte stream is converted back into a object.

Additional information

It is primarily used in serializing and deserializing a Python object structure. In other words, it’s the process of converting a Python object into a byte stream to store it in a file/database, maintain program state across sessions, or transport data over the network.

Pickling - Explanation

• It is a process of converting a object into a bytes stream and it can be stored into a file,this process also called as object serialization.

• It a module (you need to import before use).

• You need to use dump function from pickle module.

Example:

import pickle

# Python object
my_list = [30, "Python", b"I love Python"]

# Pickling
with open("data.pickle","wb") as file_handle:
    pickle.dump(my_list, file_handle, pickle.HIGHEST_PROTOCOL)

print("Pickling completed!")

# Output:
Pickling completed!

Unpickling - explanation

• It is inverse operation of pickling. Unpickling is a process where a byte stream is converted back into a object.

• This process is also called as de-serialization.

• You need to use load() function from pickle module, which is used to read an pickled object from a binary file and returns it into an object.

Example:

import pickle

# Pickling
with open("data.pickle","rb") as file_handle:
    retrieved_data = pickle.load(file_handle)
    print(retrieved_data)

# Output:

[30,"Python", b"I love Python"]

References

Pickling and unpickling

Definitions

Examples