PHP - 计算多维数组中唯一的内部数组实例

Question

I have the following array, and would like to count all instances of the inner array.

Array ( 
     [0] => Array ( [0] => b [1] => d) 
     [1] => Array ( [0] => c [1] => a) 
     [2] => Array ( [0] => b [1] => d)
     [3] => Array ( [0] => a [1] => d)
     )

I am looking at a count so that one would get:

2 of b,d

1 of c,a

1 of a,d

The outer array foreach to get get to the inner array to be done first. Not sure what is the approach in counting unique array values. Thank you.

Answer 1

function count_pairs($array) {
    foreach ($array as &$pair) {
        $pair = implode(', ', $pair);
    }
    return array_count_values($array);
}