在多维数组中计数

Question

我有一个像这样的数组:

$resellers =  Array
(
    [40] => Array
        (
            [state] => AB
            [city] => Calgary
        )

    [185] => Array
        (
            [state] => AB
            [city] => Calgary
        )

    [141] => Array
        (
            [state] => AB
            [city] => Calgary
        )

    [41] => Array
        (
            [state] => AB
            [city] => Grande Prairie
        )

    [68] => Array
        (
            [state] => BC
            [city] => Burnaby
        )

    [51] => Array
        (
            [state] => BC
            [city] => Campbell River
        )

    [61] => Array
        (
            [state] => BC
            [city] => Kamloops
        )
  )

我想知道是否有一种简单的方法可以计算"Alberta"(将是4)和BC(将是3)的值.

Answer 1

array_count_values(array_map(function($item) {
   return $item['state'];
}, $resellers));