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<?php $array = [1, 2, 3, 4]; $callable = function(&$value) { $value = $value * 100; echo $key.PHP_EOL; }; $newArray = array_map($callable, $array); print_r($newArray);
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Warning: {closure}(): Argument #1 ($value) must be passed by reference, value given in /in/DbGOh on line 9 Warning: Undefined variable $key in /in/DbGOh on line 6 Warning: {closure}(): Argument #1 ($value) must be passed by reference, value given in /in/DbGOh on line 9 Warning: Undefined variable $key in /in/DbGOh on line 6 Warning: {closure}(): Argument #1 ($value) must be passed by reference, value given in /in/DbGOh on line 9 Warning: Undefined variable $key in /in/DbGOh on line 6 Warning: {closure}(): Argument #1 ($value) must be passed by reference, value given in /in/DbGOh on line 9 Warning: Undefined variable $key in /in/DbGOh on line 6 Array ( [0] => [1] => [2] => [3] => )
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.33
Notice: Undefined variable: key in /in/DbGOh on line 6 Notice: Undefined variable: key in /in/DbGOh on line 6 Notice: Undefined variable: key in /in/DbGOh on line 6 Notice: Undefined variable: key in /in/DbGOh on line 6 Array ( [0] => [1] => [2] => [3] => )
Output for 7.3.32 - 7.3.33
Array ( [0] => [1] => [2] => [3] => )
preferences:
231.07 ms | 401 KiB | 327 Q