StringTrim

StringTrim["string"] trims whitespace from the beginning and end of the string.

StringTrim["string", patt] trims substrings matching patt.

Examples

Trim whitespace:

StringTrim["  Hello World  "]
(* "Hello World" *)

Trim specific characters:

StringTrim["###hello###", "#" ..]
(* "hello" *)

Please visit the official Wolfram Language Reference for more details.