How to match exact word anywhere in string with PHP regexp

Question

I want to find out if user has used the words admin or username anywhere in their possible username string.

So if user wants to use admin

Answer 1

This might be the pattern that you're looking for:

'#(^|\s){1}('. $needle .')($|\s|,|\.){1}#i'

Some details depend on the restrictions that you want to apply.