Merge pull request #117 from rfezzani/Fix_snake_snippet

[FIX #116] Fix snake snippet

Resolves #116

snippets/snake.md

@@ -5,16 +5,15 @@ 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.
+Break the string into words and combine them adding `_` as a separator, using a regexp.
 
 ```py
 import re
 
 def snake(str):
-  return re.sub(r"(\s|_|-)+","_",
-    re.sub(r"[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+",
-    lambda mo: mo.group(0).lower(),str)
-  )
+  return '_'.join(re.sub('([A-Z][a-z]+)', r' \1',
+    re.sub('([A-Z]+)', r' \1',
+    str.replace('-', ' '))).split()).lower()
 ```
 
 ```py