Online PHP editor | refs for vv1U3

<?php $list_of_lists_of_lists = [[1, 2, [3]], [4, 3, 4, [5, 3, 4]], 3]; $flattened_list = []; function flatten($l){ foreach ($l as $value) { if (is_array($value)) { returnflatten($value); }else{ $flattened_list[] = $value; } } return $flattened_list; } $flattened_list = flatten($list_of_lists_of_lists); print_r($flattened_list);