Tips on using the PHParray_multisort function

<?php 
$array[] = array(&#39;id&#39;=>1,&#39;price&#39;=>50);
$array[] = array(&#39;id&#39;=>2,&#39;price&#39;=>70);
$array[] = array(&#39;id&#39;=>3,&#39;price&#39;=>30);
$array[] = array(&#39;id&#39;=>4,&#39;price&#39;=>20);
foreach ($array as $key=>$value){
  $id[$key] = $value[&#39;id&#39;];
  $price[$key] = $value[&#39;price&#39;];
}
array_multisort($price,SORT_NUMERIC,SORT_DESC,$id,SORT_STRING,SORT_ASC,$array);
echo &#39;<pre class="brush:php;toolbar:false">&#39;;
print_r($array);
echo &#39;

Array
(
[0] => Array
(
[id] => 2
[price] => 70
)
[1] => Array
(
[id] => 1
[price] => 50
)
[2] => Array
(
[id] => 3
[price] => 30
)
[3] => Array
(
[id] => 4
[price] => 20
)
)