3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = range('a', 'z'); echo next($a), PHP_EOL, current($a), PHP_EOL; unset($a[key($a)]); echo current($a), PHP_EOL, key($a), PHP_EOL;;
Output for 5.6.0 - 5.6.26, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 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 - 8.2.19, 8.3.0 - 8.3.7
b b c 2
preferences:
120.65 ms | 404 KiB | 203 Q