php数组函数排序之rsort() - 对数组的元素值进行降序排序_PHP教程

$my_array = array("a" => "Dog", "b" => "Cat", "c" => "Horse");
rsort($my_array);
print_r($my_array);
?>输出：

Array
(
[0] => Horse
[1] => Dog
[2] => Cat
)
Like sort(), rsort() assigns new keys for the elements in array. It will remove any existing keys you may have assigned, rather than just reordering the keys.  This means that it will destroy associative keys.

$animals = array("dog"=>"large",  "cat"=>"medium",  "mouse"=>"small");
print_r($animals);
//Array ( [dog] => large [cat] => medium [mouse] => small )

rsort($animals);
print_r($animals);
//Array ( [0] => small [1] => medium [2] => large )

Use KSORT() or KRSORT() to preserve associative keys.