Online PHP editor | refs for RU30W

<?php function array_flatten_iterator (array $array) { foreach ($array as $value) { if (is_array($value)) { yield from array_flatten_iterator($value); } else { yield $value; } } } function array_flatten (array $array) { return iterator_to_array(array_flatten_iterator($array), false); } $array = [ 1, 2, [ 3, 4, 5, [ 6, 7 ], 8, 9, ], 10, 11, ]; var_dump(array_flatten($array));