Online PHP editor | refs for XeEBd

<?php $regions = [ 'int' => 1, 'nl' => 2, 'be' => 4, 'us' => 8, 'as' => 16, 'za' => 32, ]; for ($i = 0; $i < 1 << count($regions); $i++) array_walk(@array_filter($regions, function ($x) use ($i) { var_dump($x, $i); return $i & $x; }), function ($x, $region) use (&$list) { if (isset($list[$region])) $list[$region] .= ",$x"; else $list[$region] = $x; } ); var_dump($list);