note 90015 added to function.array-reduce

The initial value have to be int. So it is impossible to implement non-recursive flatten like this: <?php $arr = array(array(1), array(2), array(3)); $result = array_reduce($arr, 'array_merge', array()); // expected: $result == array (1, 2, 3) ?> I get: Warning: array_merge() : Argument #1 is not an array. If $initial parameter is not an int, array_reduce passes 0 (zero) to the callback function. Hayley Watson's note suggests a solution: <?php $acc = array(); foreach($arr as $a) $acc = array_merge($acc, $a); // now: $acc == array (1, 2, 3) ?> ---- Server IP: 217.73.17.12 Probable Submitter: 213.215.89.249 ---- Manual Page -- http://www.php.net/manual/en/function.array-reduce.php Edit -- https://master.php.net/note/edit/90015 Del: integrated -- https://master.php.net/note/delete/90015/integrated Del: useless -- https://master.php.net/note/delete/90015/useless Del: bad code -- https://master.php.net/note/delete/90015/bad+code Del: spam -- https://master.php.net/note/delete/90015/spam Del: non-english -- https://master.php.net/note/delete/90015/non-english Del: in docs -- https://master.php.net/note/delete/90015/in+docs Del: other reasons-- https://master.php.net/note/delete/90015 Reject -- https://master.php.net/note/reject/90015 Search -- https://master.php.net/manage/user-notes.php