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run code in 300+ PHP versions simultaneously
<?php $ids = array("8479"); $newIds = array_filter($ids, function(&$n) { $n = intVal($n); }); print_r($newIds);
Output for 8.4.1 - 8.4.12
Warning: {closure:/in/WH94Q:5}(): Argument #1 ($n) must be passed by reference, value given in /in/WH94Q on line 5 Array ( )
Output for 8.2.0 - 8.2.29, 8.3.0 - 8.3.25
Warning: {closure}(): Argument #1 ($n) must be passed by reference, value given in /in/WH94Q on line 5 Array ( )
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.33
Warning: {closure}(): Argument #1 ($n) must be passed by reference, value given in /in/WH94Q on line 7 Array ( )
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 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 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33
Array ( )

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131.51 ms | 412 KiB | 5 Q