This Python script defines a function to filter dictionary keys that are in snake_case format. Snake_case is a naming convention where words are separated by underscores and all letters are lowercase, commonly used in Python for variable names and keys in JSON data. The script provides a function called `is_snake_case` to check if a string follo…

filter_snake_case_keys.py

import re

def is_snake_case(key):
    """
    Check if a string is in snake_case format.
    
    Parameters:
        key (str): The string to check.
    
    Returns:
        bool: True if the string is in snake_case format, False otherwise.
    """
    # Define the regex pattern for snake_case
    pattern = r'^[a-z][a-z0-9_]*$'
    
    # Check if the key matches the pattern
    return bool(re.match(pattern, key))

# Example usage:
keys = ['snake_case', 'CamelCase', 'kebab-case', 'valid_key_123', '123_invalid_key']
for key in keys:
    print(f'"{key}" is snake_case: {is_snake_case(key)}')