php怎么将数组顺序反转

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);
$arr1 =array("a"=>"Volvo","b"=>"BMW","c"=>"Toyota");
echo "原数组顺序：";
var_dump($arr1);
$arr2=array_reverse($arr1);
echo "<br>数组反转后的顺序：";
var_dump($arr2);
?>

原数组顺序：array (size=3)
  'a' => string 'Volvo' (length=5)
  'b' => string 'BMW' (length=3)
  'c' => string 'Toyota' (length=6)

数组反转后的顺序：array (size=3)
  'c' => string 'Toyota' (length=6)
  'b' => string 'BMW' (length=3)
  'a' => string 'Volvo' (length=5)

array_reverse(array,preserve)