regex - How do I make a certain portion of a regular expression optional? -

How can I make some part of a regular expression optional? For example:

  \ d * [\\ s \\ w *?]   
 ... where expression inside the bracket is optional.   
 
 
 I do not think you want enough regular expressions. [\ S \ w *?] Says, "is a letter that is a place, matches a word, a star or a question mark". I think what you want ultimately (\ s \ w) *? Who says, "Match 0 or more places after the word and do not be greedy about it.  
 Though you are looking for (\ s | \) *, who says "Do not be the word or a place 0 or more often and greedy about it. "