note 106298 added to function.array-walk

I wanted to walk an array and reverse map it into a second array. I decided to use array_walk because it should be faster than a reset,next loop or foreach(x as &$y) loop. $output = array(); array_walk($input, 'gmapmark_reverse', $output); function gmapmark_reverse(&$item, $index, &$target) { $target[$item['form_key']] = $index; } In my debugger I can see that $target is progressively updated, but when array_walk returns, $output is empty. If however I use a (deprecated) call-by-reference: array_walk($input, 'gmapmark_reverse', &$output); $output is returned correctly. Unfortunately there's not an easy way to suppress the warnings: @array_walk($input, 'gmapmark_reverse', &$output); doesn't silence them. I've designed a workaround using a static array: $reverse = array(); array_walk($input, 'gmapmark_reverse'); // call function one last time to get target array out, because parameters don't work $reverse = gmapmark_reverse($reverse); function gmapmark_reverse(&$item, $index = 0) { static $target; if (!$target) { $target = array(); } if (isset($item['form_key'])) { $target[$item['form_key']] = $index; } return($target); } ---- Server IP: 69.147.83.197 Probable Submitter: 82.71.10.13 ---- Manual Page -- http://www.php.net/manual/en/function.array-walk.php Edit -- https://master.php.net/note/edit/106298 Del: integrated -- https://master.php.net/note/delete/106298/integrated Del: useless -- https://master.php.net/note/delete/106298/useless Del: bad code -- https://master.php.net/note/delete/106298/bad+code Del: spam -- https://master.php.net/note/delete/106298/spam Del: non-english -- https://master.php.net/note/delete/106298/non-english Del: in docs -- https://master.php.net/note/delete/106298/in+docs Del: other reasons-- https://master.php.net/note/delete/106298 Reject -- https://master.php.net/note/reject/106298 Search -- https://master.php.net/manage/user-notes.php