$arr1 = array( 1, 3, 2, 5, 4);
$arr2 = array(30, 30, 100, 20, 1);
array_multisort($arr1, $arr2);
print_r($arr1);
echo "<br />";
print_r($arr2);
// $arr2 corresponding to the identical entries in $arr1
/*
run:
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 )
Array ( [0] => 30 [1] => 100 [2] => 30 [3] => 1 [4] => 20 )
*/