Ruby | String gsub! Method
gsub! is a String class method in Ruby which is used to return a copy of the given string with all occurrences of pattern substituted for the second argument. If no substitutions were performed, then it will return nil. If no block and no replacement is given, an enumerator is returned instead.
Syntax: str.gsub!(pattern, replacement)
Parameters: Here, str is the given string. pattern may be specified regex or character set to be removed. replacement is the set of characters which is to be put.
Returns: A copy of the string with all occurrences of pattern substituted for the second argument or nil if no substitutions were performed.