$re = '/(\[\d{2}:\d{2}-\d{2}:\d{2}])/';
$str = '[10:42-23:10]part1[11:30-13:20]part2[4][5]';
preg_match_all($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