A regex that validates a web address and matches an empty string?

Question

The current expression validates a web address (HTTP), how do I change it so that an empty string also matches?

(http|https):\\/\\/[\\w\\-_]+(\\.[\\w\\-_]+)+         


        

Answer 1

Expr? where Expr is your URL matcher. Just like I would for http and https: https?. The ? is a known as a Quantifier -- you can look it up. From Wikipedia:

? The question mark indicates there is zero or one of the preceding element.