按子阵列计数对多维数组进行排序

Question

排序数组时遇到问题。

我有一个像我这样的类别的数组：

Array
(
    [0] => Array
        (
            [title] => category
            [url] => http//mycategoryurl
            [subcategory] => Array
                (
                    [0] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [1] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [2] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                )
        )
    [1] => Array
        (
            [title] => category
            [url] => http//mycategoryurl
            [subcategory] => Array
                (
                    [0] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [1] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [2] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [3] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                )
        )
    [2] => Array
        (
            [title] => category
            [url] => http//mycategoryurl
            [subcategory] => Array
                (
                    [0] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [1] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                )
        )
)

我希望count(subcategory)像这样对这个数组进行排序：

Array
(
    [0] => Array
        (
            [title] => category
            [url] => http//mycategoryurl
            [subcategory] => Array
                (
                    [0] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [1] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [2] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [3] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                )
        )
    [1] => Array
        (
            [title] => category
            [url] => http//mycategoryurl
            [subcategory] => Array
                (
                    [0] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [1] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [2] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                )
        )
    [2] => Array
        (
            [title] => category
            [url] => http//mycategoryurl
            [subcategory] => Array
                (
                    [0] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                    [1] => Array
                        (
                            [title] => category - first
                            [url] => http//mycategoryurl
                        )
                )
        )
)

请帮我按照我的例子对这个数组进行排序。

Answer 1

您想要使用usort功能，如下所示：

usort($arrayToSort, function($a, $b){
    $aCount = count($a['subcategory']);
    $bCount = count($b['subcategory']);
    if ($aCount  == $bCount) {
        return 0;
    }

    //flip the '>' to '<' for ascending sort. It is set to do descending 
    return ($aCount > $bCount) ? -1 : 1;

});

Answer 2

使用usort函数进行回调：

$arr = array(); // your array
usort($arr, function($a, $b) { return count($a['subcategory']) < $count($b['subcategory'])? -1 : 1; });
print_r($arr);