3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = [ 7 => [49 => null, 41 => null], 8 => [70 => null, 69 => null], 105 => null, 9 => null, 10 => null ]; array_walk_recursive($array, fn(&$v, $k) => $v = $k); var_export($array);
Output for 7.4.0 - 7.4.33, 8.0.1 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
array ( 7 => array ( 49 => 49, 41 => 41, ), 8 => array ( 70 => 70, 69 => 69, ), 105 => 105, 9 => 9, 10 => 10, )

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