3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = [1,[2,[3,[4,[5,6,7]]]],8,9]; $b = [1,[2,[3,[4,[5,6,0]]]],8,9]; $a = array_map(fn(int|array $element) => is_int($element) ? [$element] : $element, $a); $b = array_map(fn(int|array $element) => is_int($element) ? [$element] : $element, $b); $key = key(array_diff_assoc(array_merge(...$a), array_merge(...$b))); var_dump(array_merge(...$a)); var_dump(array_merge(...$b)); var_dump($key);

preferences:
25.61 ms | 408 KiB | 5 Q