Question

I need to strip unwanted characters from a string. I want to use preg replace, but I am useless at regular expressions.

My string should only allow a-z A-Z 0-9 and spaces. No other characters.

So for example:

some string's-are#bad

would become:

some stringsarebad

Many thanks

Answer 1

You can use this:

$string = preg_replace('/[^a-z0-9 ]/i', '', $string);

To explain this:

• / opening delimiter — start the regex
• [^ start negative character group — match anything except what’s in this selection
• a-z0-9 match alphabetic and numeric characters and spaces
• ] close character group
• / closing delimiter
• i case insensitive search — match A-Z as well