---
title: snake
tags: string,regexp,intermediate
---

Converts a string to snake case.

Break the string into words and combine them adding `_` as a separator, using a regexp.

```py
import re

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

```py
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_smal_things"
```