the php function preg_match()
stackoverflow.com/questions/10358300/preg-match-array-items-...
This is a stackoverflow thread on this topic.
www.codingforums.com/php/34709-preg_match-syntax.html
This thread shows you clearly how to use preg_match() and explains the different switches.
stackoverflow.com/questions/10201337/what-do-the-symbols-mea...
I have this expression in a code snippet i borrowed offline. It forces the new users to have a password that not only requires upper+lower+numbers but they must be in that order! If i enter lower+upper+numbers, it fails!
if ...Visited76