3v4l.org

run code in 300+ PHP versions simultaneously
<?php $some_array = array (0 => 1, 2 => 1, 'a' => 1, 1 => 1, 'z' => 1, 'x' => 1); ksort($some_array); echo(join("", array_keys($some_array)));
Output for 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
012axz
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 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
0axz12
preferences:
258.43 ms | 404 KiB | 332 Q