Great thanks, graff!

I appreciate your re-writing the code. It's definitely a lot easier to read and understand than the one I've (btw, does your cover the exact length part i.e if the string has to be exactly a certain length? I'll test that out later when I get home.)

I think I misunderstood the regex part. Thanks for pointing out :)

update

Note that the case of $min==$max does not need special treatment

Missed that out earlier.