3v4l.org

run code in 300+ PHP versions simultaneously
<?php var_dump(preg_replace('~(?<!^ {0,50}) //~', '-', ' // x // y'));
Output for 7.4.0 - 7.4.30, 8.0.1 - 8.0.23, 8.1.0 - 8.1.10
Warning: preg_replace(): Compilation failed: lookbehind assertion is not fixed length at offset 0 in /in/qoEooV on line 3 NULL

preferences:
17.99 ms | 409 KiB | 5 Q