$re = '/([\s,.\/]\s*)?y+[.\/]?/m';
$str = 'MMM d, y, h:mm a
d MMM y, HH:mm
y年M月d日 ah:mm
dd.MM.y, HH:mm
y. M. d. a h:mm
d MMM y \'г\'., HH:mm
dd MMM y, HH:mm
y/MM/dd H:mm
d. MMM y, HH:mm
dd/MM/y h:mm a
dd.M.y HH:mm
d MMM y HH:mm" ';
preg_match_all($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