note 114491 added to function.array-reduce

You can effectively ignore the fact $result is passed into the callback by reference. Only the return value of the callback is accounted for. <?php $arr = [1,2,3,4]; var_dump(array_reduce( $arr, function(&$res, $a) { $res += $a; }, 0 )); # NULL ?> <?php $arr = [1,2,3,4]; var_dump(array_reduce( $arr, function($res, $a) { return $res + $a; }, 0 )); # int(10) ?> Be warned, though, that you *can* accidentally change $res if it's not a simple scalar value, so despite the examples I'd recommend not writing to it at all. ---- Server IP: 87.124.126.49 Probable Submitter: 31.24.0.198 ---- Manual Page -- http://php.net/manual/en/function.array-reduce.php Edit -- https://master.php.net/note/edit/114491 Del: integrated -- https://master.php.net/note/delete/114491/integrated Del: useless -- https://master.php.net/note/delete/114491/useless Del: bad code -- https://master.php.net/note/delete/114491/bad+code Del: spam -- https://master.php.net/note/delete/114491/spam Del: non-english -- https://master.php.net/note/delete/114491/non-english Del: in docs -- https://master.php.net/note/delete/114491/in+docs Del: other reasons-- https://master.php.net/note/delete/114491 Reject -- https://master.php.net/note/reject/114491 Search -- https://master.php.net/manage/user-notes.php