3v4l.org

run code in 300+ PHP versions simultaneously
<?php $year = ''; echo (preg_match('/^[0-9]{4}$/', $year)) ? 'yes' : 'no';
Output for 5.6.0 - 5.6.24, 7.0.0 - 7.0.20, 7.1.0 - 7.1.7, 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
no
preferences:
154.84 ms | 403 KiB | 180 Q