3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = ['blah']; $key = 'foo'; $val = $arr[$key] ?? null; unset($arr[$key]); echo $val; var_dump($arr);
Output for 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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
array(1) { [0]=> string(4) "blah" }
Output for 5.4.2 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28
Parse error: syntax error, unexpected '?' in /in/9AcrU on line 6
Process exited with code 255.
preferences:
237.18 ms | 402 KiB | 256 Q