3v4l.org

run code in 300+ PHP versions simultaneously
<?php $date = "13/23/15"; echo $x = '~^(?:' . implode('|', range(1, 12)) . ')\/(?:' . implode('|', range(1, 31)) . ')\/[0-9]{2}$~'; preg_match($x, $date, $m); var_dump($m);
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
~^(?:1|2|3|4|5|6|7|8|9|10|11|12)\/(?:1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31)\/[0-9]{2}$~array(0) { }

preferences:
235.12 ms | 406 KiB | 312 Q