Python - Working with JSON Files

Working with JSON Files in Python

In Python, a module will help us to work with JSON which is a built-in JSON module, which allows us to convert between JSON and Python data types. Here's a quick guide on how to handle JSON files in Python.

Computers can easily analyze and create JSON (JavaScript Object Notation), a lightweight format for exchanging data that is simple for people to read and write.

Basic Operation of JSON file.

1. Reading a JSON File: Load a JSON file and convert it into a Python dictionary or list.
2. Writing to a JSON File: It converts the Python dictionary or list into a JSON file.
3. Modifying JSON data: It helps us load, modify, and write back the changes.

Reading a JSON File

Reading a JSON file in Python is a basic concept while handling the data in Python. Python has a built-in package called JSON, which can be used to work with JSON data. This is done using the JSON module, which gives us several methods to help us read the JSON file in the loads() and load() methods.

import json

Example

Following is a code example of reading a JSON file.

# Opening and reading a JSON file
with open('data.json', 'r') as file:
    data = json.load(file)
# Now `data` is a Python dictionary (or list depending on the JSON structure)
print(data)

Writing a JSON File

Writing a JSON file in Python converts Python objects such as directories and lists into JSON format and saving to a file.

Example

Following is a code example of Writing a JSON File.

import json
# Python dictionary to write into JSON
data = {
    'name': 'Aman',
    'age': 25,
    'city': 'New York'
}
# Writing the dictionary into a JSON file
with open('data.json', 'w') as file:
    json.dump(data, file, indent=4) # `indent=4` makes the file more readable

Modify JSON Data

Modifying JSON data in Python loads an existing JSON file into a Python object such as a dictionary or list, making the necessary changes to that object, and then saving the updated data to the JSON file.

Example

Following is the code example for modifying the JSON Data.

Let’s assume we have JSON data:
{
    "name": "Aman",
    "age": 25,
    "city": "Los Angeles",
    "skills": ["Python", "ReactJS", "Node.js"]
}

Now Modify the above JSON Data:

import json
# Read the JSON data from the file
with open('data.json', 'r') as file:
    data = json.load(file)

# Modify the data
# Let's change the city, add a new skill, and update the age
data['city'] = 'India'
data['skills'].append('Django')
data['age'] = 26

# Write the modified data back to the file
with open('data.json', 'w') as file:
    json.dump(data, file, indent=4)

JSON String

We can also work on the JSON string directly using the json.loads() and Json.dumbs(), where loads() Reads JSON from a file and converts it to a Python object, and dumbs() writes a Python object to a file in JSON format.

Example

Let’s demonstrate the above method using an example:

# Convert JSON string to Python object:
json_str = '{"name": "Aman", "age": 25, "city": "Delhi"}'
data = json.loads(json_str)
print(data) # Output will be a Python dictionary

# Convert Python object to JSON string:
data = {'name': 'Aman', 'age': 25, 'city': 'Delhi'}
json_str = json.dumps(data, indent=4)
print(json_str) # Output will be a JSON-formatted string