note 106684 added to function.array-map

Note that the $arr argument has to be an array, not just a Traversable/Iterator. For instance this won't work: <?php $documents = $mongo->db->collection->find(); // $documents is Traversable by foreach $ids = array_map(function($document) { return $document['_id']; }, $objects); // $ids will now be NULL, because $documents wasn't an Array ?> A solution is to first use iterator_to_array(): <?php $ids = array_map(function($document) { return $document['_id']; }, iterator_to_array($objects)); // $ids will now be an array of ['_id']s ?> But this is not very efficient: two cycles instead of one. Another solution is to use foreach: one cycle and a lot of freedom (and in the same scope). ---- Server IP: 91.199.167.223 Probable Submitter: 213.125.116.82 ---- Manual Page -- http://www.php.net/manual/en/function.array-map.php Edit -- https://master.php.net/note/edit/106684 Del: integrated -- https://master.php.net/note/delete/106684/integrated Del: useless -- https://master.php.net/note/delete/106684/useless Del: bad code -- https://master.php.net/note/delete/106684/bad+code Del: spam -- https://master.php.net/note/delete/106684/spam Del: non-english -- https://master.php.net/note/delete/106684/non-english Del: in docs -- https://master.php.net/note/delete/106684/in+docs Del: other reasons-- https://master.php.net/note/delete/106684 Reject -- https://master.php.net/note/reject/106684 Search -- https://master.php.net/manage/user-notes.php