3v4l.org

run code in 300+ PHP versions simultaneously
<?php function cluster($array) { $array = array_reverse($array); foreach($array as $element) { $newarray = [$element=>$newarray]; } return $newarray; } var_dump(cluster(['A', 'B', 'C', 'D','E','F','G','H','I']));

preferences:
47.25 ms | 402 KiB | 5 Q