PHP Using RegEx to get substring of a string

Question

I\'m looking for an way to parse a substring using PHP, and have come across preg_match however I can\'t seem to work out the rule that I need.

I am parsing a web p

Answer 1

$string = "producturl.php?id=736375493?=tm";
$number = preg_replace("/[^0-9]/", '', $string);