snake python Code Snippet in 2025

Converts a string to snake case.

• Use re.sub() to match all words in the string, str.lower() to lowercase them.
• Use re.sub() to replace any - characters with spaces.
• Finally, use str.join() to combine all words using - as the separator.

from re import sub

def snake(s):
  return '_'.join(
    sub('([A-Z][a-z]+)', r' \1',
    sub('([A-Z]+)', r' \1',
    s.replace('-', ' '))).split()).lower()

snake('camelCase') # 'camel_case'
snake('some text') # 'some_text'
snake('some-mixed_string With spaces_underscores-and-hyphens')
# 'some_mixed_string_with_spaces_underscores_and_hyphens'
snake('AllThe-small Things') # 'all_the_small_things'