Converting JSON Key Names from CamelCase to Underscores

2 min read 09-11-2024

Converting JSON Key Names from CamelCase to Underscores

When working with JSON data, you might encounter key names in CamelCase format (e.g., firstName, lastName). However, for certain applications or coding standards, you may need to convert these key names into a more readable format using underscores (e.g., first_name, last_name). This article will guide you through the process of converting JSON key names from CamelCase to underscores.

Why Convert CamelCase to Underscores?

Converting CamelCase to underscores can improve readability and consistency in your code, particularly when integrating with systems or languages that favor snake_case (underscored naming convention). Additionally, it can simplify data processing in some frameworks.

Example of JSON Key Name Conversion

Original JSON Structure

{
    "firstName": "John",
    "lastName": "Doe",
    "emailAddress": "[email protected]"
}

Desired JSON Structure

{
    "first_name": "John",
    "last_name": "Doe",
    "email_address": "[email protected]"
}

Steps for Conversion

1. Using a Programming Language

You can write a simple function in Python to automate this conversion. Here’s how you can do it:

import json
import re

def camel_case_to_underscore(key):
    # Convert CamelCase to snake_case
    return re.sub('([a-z])([A-Z])', r'\1_\2', key).lower()

def convert_json_keys(data):
    if isinstance(data, dict):
        return {camel_case_to_underscore(k): convert_json_keys(v) for k, v in data.items()}
    elif isinstance(data, list):
        return [convert_json_keys(item) for item in data]
    else:
        return data

# Sample JSON data
json_data = '{"firstName": "John", "lastName": "Doe", "emailAddress": "[email protected]"}'

# Convert JSON string to Python dictionary
data_dict = json.loads(json_data)

# Convert keys
converted_data = convert_json_keys(data_dict)

# Print result
print(json.dumps(converted_data, indent=4))

2. Using Command Line Tools

If you're more comfortable using command line tools, jq is a powerful tool for working with JSON. However, more complex transformations like converting CamelCase to underscores may require custom scripts. You can use a simple script with sed or a similar command-line text processor, but keep in mind that it may not be as robust as a programming solution.

Conclusion

Converting JSON key names from CamelCase to underscores can enhance the readability of your data and improve integration with other systems. Whether you choose to use a programming approach or a command-line tool, automating this process can save time and reduce errors in your code.

By following the methods outlined above, you can easily adapt your JSON data to meet your specific needs.