How To Save a Dictionary To A File In Python – Definitive Guide

Python dictionary allows you to store values in a key-value format.

You can save a dictionary to a file in Python using the json.dump(yourdict,fileobj) statement.

Basic Example

import json

json_filename = 'yourdict.csv'

yourdict = {'Name': 'Ram', 'Job': 'Expert', 'Salary': '90000'}

with open(json_filename, 'w') as f:

    json.dump(yourdict,f)

Output

{"Name": "Ram", "Job": "Expert", "Salary": "90000"}

Let us learn how to write a dictionary in a different file format based on different use cases.

Save Dictionary To Json File

JSON is a lightweight data-interchange format. You can use this format when you want to transfer data over a network.

To save a dictionary to a JSON file using the dump() method,

• Open a json file in a write mode. If the file doesn’t exist, the open() method will create it.
• Use the dump() method to write the dictionary to the file object.

To learn more details about writing a dictionary to a JSON file, read: How To Dump A Dictionary Into A JSON File in Python

Code

import json

json_filename = 'yourdict.json’

yourdict = {'Name': 'Ram', 'Job': 'Expert', 'Salary': '90000'}

with open(json_filename, 'w') as f:

    json.dump(yourdict,f)

Output

The JSON file will look like the one below.

{"Name": "Ram", "Job": "Expert", "Salary": "90000"}

Save Dictionary To CSV File

CSV is a comma-separated values file. It is easy to create and faster to handle.

To save a dictionary to a CSV file, use the csv.DictWriter.

• Open a CSV file in write mode. If the file doesn’t exist, the open() method will create it.
• Create a DictWriter object with the file object, desired delimiter and fieldnames to use as a header.
• Use the writeheader() method to write the header in the file. The keys in the dictionary will be written as headers. This is optional.
• Use the writerow() method and pass the dictionary to write the values of the dictionary keys as data rows.

Code

import csv

csv_filename = 'yourdict.csv'

yourdict = {'Name': 'Ram', 'Job': 'Expert', 'Salary': '90000'}

with open(csv_filename, 'w') as f:

    writer = csv.DictWriter(f, delimiter=',', fieldnames = ('Name', 'Job', 'Salary'))

    #Optional
    writer.writeheader()

    writer.writerow(yourdict)

Output

Name,Job,Salary
Ram,Expert,90000

Save Dictionary To Text File

Text files are standard files, and they don’t contain any special formatting.

To save a dictionary to a text file, use the file.write() method.

• Open a text file in write mode. If the file doesn’t exist, the open() method will create it.
• Open the file object using the file open() method.
• Convert the dictionary to String and write it to the dictionary using the write() method.

Code

txt_filename = 'yourdict.txt'

yourdict = {'Name': 'Ram', 'Job': 'Expert', 'Salary': '90000'}

with  open(txt_filename, 'w') as f :

    f.write(str(yourdict))

Output

{'Name': 'Ram', 'Job': 'Expert', 'Salary': '90000'}

Saving Dictionary To File Using Pickle

Pickle files store python objects as a byte stream that can be stored in a database or transported data over a network.

In other words, this is also known as pickling or serialisation.

To save a dictionary to a pickle file, use the pickle.dump().

• Open a text file in write AND binary mode using wb. If the file doesn’t exist, the open() method will create it.
• Open the file object using the file open() method.
• Dump the dictionary using the pickle.dump() method.

Code

import pickle

pickle_filename = 'yourdict.pkl'

yourdict = {'Name': 'Ram', 'Job': 'Expert', 'Salary': '90000'}

with  open(pickle_filename, 'wb')  as f:

     pickle.dump(yourdict,f)

It is not possible to open the pickle file in the jupyter notebook. If you open it in any other editor, you’ll see the byte characters, and it is not a human-readable format.

Loop Through Dictionary And Write To File

This section demonstrates how to loop through the dictionary and write the contents to a file.

• Open the file in the append mode using a.
• Use the dict.items() method and iterate over the dictionary items. It returns one key-value pair during each iteration.
• Write the value to the file using the file.write() method.

Code

yourdict = {'Name': 'Ram', 'Job': 'Expert', 'Salary': '90000'}

txt2_filename = 'yourdict.txt'

with  open(txt2_filename, 'a')  as f:

    for (key, val) in  yourdict.items() :

        itemstr = key +' : ' + val +'\n'

         f.write(itemstr)

Output

Name : Ram
Job : Expert
Salary : 90000

Write Dictionary To File Line By Line

This section teaches you how to write a dictionary to a file line by line.

• Open the file in the append mode using a.
• Use the dict.items() method and iterate over the dictionary items. It returns one key-value pair during each iteration.
• Write the value to the file using the file.write() method.
• each entry in the dictionary will be written as a new line in the file.

Code

yourdict = {'Name': 'Ram', 'Job': 'Expert', 'Salary': '90000'}

txt2_filename = 'yourdict.txt'

with  open(txt2_filename, 'a')  as f:

    for (key, val) in  yourdict.items() :

        itemstr = key +' : ' + val +'\n'

        f.write(itemstr) 

Output

Name : Ram
Job : Expert
Salary : 90000

Additional Resources

• How to Convert Dictionary To Pandas Dataframe in Python
• How To Convert A CSV file into A Dictionary in Python