Merge two arrays and sort them as numbers, in descending order in PHP

Description

The following code shows how to merge two arrays and sort them as numbers, in descending order.

Example

//from ww w  .  j  a  v a2  s.c  om
<?php
    $a1=array(1,3,15,7,5);
    $a2=array(4,3,20,1,6);
    $num=array_merge($a1,$a2);
    array_multisort($num,SORT_DESC,SORT_NUMERIC);
    print_r($num);
?>

The code above generates the following result.