Online PHP editor | output for IIDcQ

<?php $a = []; $keys = [ 'array' => [], 'object' => new stdClass, 'closure' => function () {}, 'class' => new class {}, 'class with tostring' => new class {function __toString(){return 'to string class';}}, 'resource' => fopen(__FILE__, 'r'), ]; foreach ($keys as $desc =>$key) { echo "===" . $desc . "===\n"; $a[$key] = true; echo "state of array: \'n" var_dump($a); echo "state of key: \n" var_dump($key); echo "is the key set in the array: \n" var_dump(isset($a[$key])); } echo "===============\n"; var_dump($a);