Question

I’m trying to match letters C D F H I E1 E2 CR (case insensitive) and came up with this. It’ll match a single letter but wont match the E1 E2 CR. Actually it should. Whats the right way to do this?

preg_match('/^([C]|[D]|[F]|[H]|[I]|[E1]|[E2]|[CR]?)$/','CR')

Answer 1

Given the fairly limited and specific set of codes you’re checking, I’d suggest using

in_array($inputvalue,array('C','D','F','H','I','E1','E2','CR'));

rather than a regex — it’ll run quicker than a regex and be easier to undersand and modify later on.