php – 合并多个数组,然后按数组值计数排序

请帮助我,我需要合并多个数组,然后按数组值计数排序.以下是问题：

$array1 = array("abc","def","ghi","jkl","mno");
$array2 = array("mno","mno","pqr","stu");
$array3 = array_merge($array1,$array2);
$array4 = ???

print_r($array4);

我想要$array4的返回值如下：

Array
(
[0] => mno
[1] => ghi
[2] => jkl
[3] => abc
[4] => def
[5] => pqr
[6] => stu
)

你可以做：

$array1 = array("abc",$array2);

// get the array of count.
$array4 = array_count_values($array3);

// sort it in reverse order.
arsort($array4);

// extract just the keys.
$array4 = array_keys($array4);

Working example