How do I allow spaces in this regex?

Question

I\'m such an amateur at regex, how do I allow spaces(doesn\'t matter how many) in this regex?

if(preg_match(\'/[^A-Za-z0-9_-]/\', $str)) return FALSE;
         


        

Answer 1

You only need to add a literal blank space in your negated character class.

It would be more concise to use:

• the case-insensitive flag i and omit one of the letter ranges
• and write [0-9] as \d

like this:

if (preg_match('/[^A-Z0-9_ -]/i', $str)) return FALSE;

but even better would be to use \w which represents [A-Za-z0-9_] (which is most of your pattern) to write:

if (preg_match('/[^\w -]/', $str)) return FALSE;

This pattern states that if $str contains any character not in [A-Za-z0-9_ -] then false will be returned.