How to read and write JSON files in Python

Using Python to Read, Write, and Manipulate JSON Files

JSON (JavaScript Object Notation) is a popular data interchange format that is easy for humans to read and write. JSON often comes into play when interacting with web APIs or HTTP requests within the field of programming. Python provides built-in support for working with JSON files through the json module. In this article, we will discuss how to use Python to read, write, and manipulate JSON files.

Reading JSON Files

To read a JSON file in Python, you can follow these steps:

1. Import the json module.
2. Open the JSON file using Python's open() function with the mode set to r.
3. Use the json.load() function to load the contents of the file as a Python dictionary.

Here is an example code snippet that demonstrates how to read a JSON file:

import json

# Open the JSON file
with open('data.json') as f:
    data = json.load(f)

# Print the data (it will be stored as a Python dictionary)
print(data)

Writing JSON Files

To write data to a JSON file in Python, you can use the json module as well. Here are the steps to write data to a JSON file:

1. Define the data that you want to write as a Python dictionary.
2. Open a new file using Python's open() function.
3. Use the json.dump() function to write the dictionary data to the file in JSON format.

Here is an example code snippet that demonstrates how to write data to a JSON file:

import json

# Define the data as a Python dictionary
data = {
    'name': 'Bob',
    'age': '25',
    'city': 'Los Angeles'
}

# Write data to a JSON file
with open('output.json', 'w') as f:
    json.dump(data, f)

You can read the output.json file, modify the data dictionary by adding a new key-value pair, and then save it as another JSON file. Here's an example code snippet to achieve that:

# Read the data from the written file and print it
with open('output.json') as f:
    output_data = json.load(f)
    print(output_data)

# Modify the data by adding a new key-value pair
output_data['job'] = 'Engineer'

# Write the modified data to a new JSON file
with open('modified_output.json', 'w') as f:
    json.dump(output_data, f)
    
# Read the modified data from the newly written file and print it
with open('modified_output.json') as f:
    modified_data = json.load(f)
    print('Modified data:', modified_data)

In this code snippet:

• We first read the data from the output.json file.
• We then modify the output_data dictionary by adding a new key-value pair.
• The modified data is then written to a new JSON file named modified_output.json.
• Finally, we read the modified data from modified_output.json and print it.

Conclusion

In conclusion, Python's json module makes it simple to work with JSON files. You can read, write, and manipulate JSON data using Python's built-in functions, making it a powerful tool for handling JSON data in your Python projects.

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