$re = '/ \d{1,2}[д]\d{1,2}[ч]\d{1,2}[м]\d{1,2}[с]|\d{1,2}[м]\d{1,2}[с]/';
$str = ' 25д10ч3м10с
15м30с';
preg_match_all($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