How to match hyphens with Regular Expression?

Question

How to rewrite the [a-zA-Z0-9!$* \\t\\r\\n] pattern to match hyphen along with the existing characters ?

Answer 1

Escape the hyphen.

[a-zA-Z0-9!$* \t\r\n\-]

UPDATE:
Never mind this answer - you can add the hyphen to the group but you don't have to escape it. See Konrad Rudolph's answer instead which does a much better job of answering and explains why.