$re = '/#(?P<_id>[0-9]+) @ (?P<left>[0-9]+),(?P<top>[0-9]+): (?P<width>[0-9]+)x(?P<height>[0-9]+)/m';
$str = '#1 @ 1,3: 4x4
#2 @ 3,1: 4x4
#3 @ 5,5: 2x2';
preg_match_all($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