3v4l.org

run code in 300+ PHP versions simultaneously
<?php $x = 'k5'; echo preg_replace('/k(\d+)/', '-${1}', $x);
Output for 7.4.0 - 7.4.33, 8.0.1 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
-5

preferences:
115.11 ms | 402 KiB | 120 Q