Remove everything after @ til next space until no more matches are found?

You may use this re.sub:

@\w+\s*

Code:

>>> s = "Hello @StackOverflow! How are you today? I'd like to !sh @StackExchange"
>>> print ( re.sub(r'@\w+\s*', '', s) )
Hello ! How are you today? I'd like to !sh

RegEx Details:

• @: Match literal @:
• \w+\s*: Match 1+ word characters followed by 0 or more whitespaces