preg_replace ranged out - compilation failed

Question

In my code:

$c = preg_replace('#[^a-z0-9áčďéěíňóřšťúůýž_-:().,;!?]#i', '', $_POST['c']);

I get this error:
Warning: preg_replace() [function.preg-replace]: Compilation failed: range out of order in character class at offset 40

IDK where could be the error.

Answer 1

Do this way:

$c = preg_replace('#[^a-z0-9áčďéěíňóřšťúůýž_\-:().,;!?]#i', '', $_POST['c']);

you need to escape - inside square brackets [..] because it's treated as interval specifier