Online PHP editor | refs for i10rJ

<?php $r1 = [ 1 => [1, 2, "one"], 2 => [5, 5, "two"], ]; $r2 = [ 1 => [null, 20, "one"], 2 => [1, 0, "two"], ]; $sum = function (array $a1, array $a2) { return array_map( function($e1) { return (is_int($e1) || is_null($e1)) ? array_sum(func_get_args()) : $e1; }, $a1, $a2 ); }; $res = []; foreach ($r1 as $k => $a) { $res[$k] = $sum($r1[$k], $r2[$k]); } var_dump($res);