preg match - PHP preg_match and preg_match_all functions

Question

I would like to know what the preg_match and preg_match_all functions do and how to use them.

Answer 1

preg_match stops looking after the first match. preg_match_all, on the other hand, continues to look until it finishes processing the entire string. Once match is found, it uses the remainder of the string to try and apply another match.

http://php.net/manual/en/function.preg-match-all.php