$re = '/page\?[^#]*\buid=(\d+)(?:[^#]*#(\d+))?/';
$str = 't3://page?uid=2879&L=1#23260
t3://page?uid=2879#23263
t3://page?uid=2881&L=0
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php