3v4l.org

run code in 300+ PHP versions simultaneously
<?php $some_array = array ( 0 => 1, 'x' => 1, 2 => 1, 'a' => 1, 1 => 1, 'z' => 1); ksort($some_array); var_dump($some_array); echo(join("", array_keys($some_array)));

preferences:
38.12 ms | 402 KiB | 5 Q