3v4l.org

run code in 300+ PHP versions simultaneously
<?php $x = 'k5'; echo preg_replace('/k(\d+)/', '-${1}1', $x);
Output for 7.4.0 - 7.4.30, 8.0.1 - 8.0.23, 8.1.0 - 8.1.10, 8.2rc1
-51

preferences:
17.75 ms | 409 KiB | 5 Q