How to Save a Dictionary to a File in Python

This tutorial explains multiple methods to save a dictionary to a file in Python language. Methods include:

• dump() function of pickle module of Python
• save() function of NumPy library
• dump() function of Python json module.

Save a Dictionary to File in Python Using the dump Function of the pickle Module

The code example below shows how we can use the dump() function of the pickle module to save the dictionary and read a dictionary from the saved file using the load() function. The dump() function of the pickle module needs the dictionary which we want to save, and the file object as parameters to save the dictionary as a .pkl file.

import pickle

my_dict = {"Apple": 4, "Banana": 2, "Orange": 6, "Grapes": 11}

with open("myDictionary.pkl", "wb") as tf:
    pickle.dump(my_dict, tf)

The below code example shows how to read the dictionary saved in a file, using the load() function. The load() function needs a file object as a parameter to load the dictionary from the .pkl file.

import pickle

with open("myDictionary.pkl", "wb") as tf:
    new_dict = pickle.load(tf)

print(new_dict)

Output:

{ 'Apple': 4, 'Banana': 2, 'Orange': 6, 'Grapes': 11}

Save a Dictionary to File in Python Using the save Function of NumPy Library

The save() function of the NumPy library can also save a dictionary in a file. In order to save the dictionary as a .npy file, the save() function requires the file name and dictionary which we want to save, as parameters to save the dictionary to a file.

Code example:

import numpy as np

my_dict = {"Apple": 4, "Banana": 2, "Orange": 6, "Grapes": 11}
np.save("file.npy", my_dict)

The code example shows how to read the Python dictionary saved as .npy file. The load() function of NumPy library requires the file name and need to set allow_pickle parameter as True to load the saved dictionary from .npy file.

Code example:

import numpy as np

new_dict = np.load("file.npy", allow_pickle="TRUE")
print(new_dict.item())

Save a Dictionary to File in Python Using the dump Function of the json Module

Another method to save a dictionary to file in Python is to use the dump() function of the json module. It also needs dict variable which we want to save, and file object as parameters to save the dictionary as .json file

Example code:

import json

my_dict = {"Apple": 4, "Banana": 2, "Orange": 6, "Grapes": 11}

tf = open("myDictionary.json", "w")
json.dump(my_dict, tf)
tf.close()

Code example to read the dictionary saved as a file using the load function of the json module is shown below. The load() function needs file object as parameter to load the dictionary from the .json file.

import json

tf = open("myDictionary.json", "r")
new_dict = json.load(tf)
print(new_dict)