3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a="a / b"; $a=preg_replace('/\//','\\',$a); echo "First version: {$a}\n"; $a=preg_replace('/\//','\\\\',$a); echo "Second version: {$a}\n"; ?>
Output for 5.6.0 - 5.6.25, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
First version: a \ b Second version: a \ b
preferences:
132.41 ms | 408 KiB | 5 Q