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 page and need to grab a numeric value from the string, the string is like this
$matches = array(); preg_match('/id=([0-9]+)\?/', $url, $matches);
This is safe for if the format changes. slandau's answer won't work if you ever have any other numbers in the URL.