note 75304 deleted from control-structures.foreach by tularis

Note Submitter: Schraalhans Keukenmeester ---- The documentation states foreach uses a copy of an array unless it's referenced. The example uses foreach ($arr as &$element) { if (condition) { change element; } } One reason never to modify array values directly in a foreach: $arr = array (1,3,5,8,11,19); foreach ($arr as $key=>$value) { if ($value %2 != 0) $arr['oddcount'] += 1; } echo $arr['oddcount']; //output: 5, as expected. But: $arr = array (1,3,5,8,11,19); $ref = &$arr; // create a reference, outside the loop. foreach ($arr as $key=>$value) { if ($value %2 != 0) $arr['oddcount'] += 1; } echo $arr['oddcount']; //output: 6 !!! Since it isn't always clear where in the code a reference is made to the array, the behaviour of any foreach loop modifying array elements directly becomes unpredictable. If you want to change array values inside a foreach, create your own array and copy it back after the loop. (Thanks to Gosha Bine.)