3v4l.org

run code in 300+ PHP versions simultaneously
<?php $s = "q w e r t y"; $t = preg_replace('/\s+/', ' ', $s); print($t);
Output for 7.3.0 - 7.3.33, 7.4.0 - 7.4.30, 8.0.0 - 8.0.20, 8.1.0 - 8.1.7
q w e r t y

preferences:
30.62 ms | 409 KiB | 5 Q