php - 无法按内部项目对多维数组进行排序

Question

我想按内部数组项的数量（ count() ）降序（即大多数项优先）对数组进行排序

这是我的数组，

Array
(
    [Itm01] => Array
        (
            [0] => Array
                (
                    [id] => 238
                    [col1] => 7908
                    [col2] => 7181
                )

            [1] => Array
                (
                    [id] => 17024
                    [col1] => 1039
                    [col2] => 7181
                )

            [2] => Array
                (
                    [id] => 
                    [col1] => 1039
                    [col2] => 7181
                )

        )

    [Itm02] => Array
        (
            [0] => Array
                (
                    [id] => 260
                    [col1] => 1039
                    [col2] => 8964
                )

            [2] => Array
                (
                    [id] => 238
                    [col1] => 9149
                    [col2] => 8964
                )

            [3] => Array
                (
                    [id] => 238
                    [col1] => 0
                    [col2] => 8964
                )

            [4] => Array
                (
                    [id] => 238
                    [col1] => 7333
                    [col2] => 8964
                )

            [5] => Array
                (
                    [id] => 238
                    [col1] => 9049
                    [col2] => 8964
                )

            [6] => Array
                (
                    [id] => 238
                    [col1] => 7333
                    [col2] => 8964
                )

            [7] => Array
                (
                    [id] => 238
                    [col1] => 9049
                    [col2] => 8964
                )

            [8] => Array
                (
                    [id] => 238
                    [col1] => 8217
                    [col2] => 8964
                )

            [9] => Array
                (
                    [id] => 238
                    [col1] => 7516
                    [col2] => 8964
                )

            [10] => Array
                (
                    [id] => 82
                    [col1] => 1039
                    [col2] => 8964
                )

        )

    [Itm03] => Array
        (
            [0] => Array
                (
                    [id] => 238
                    [col1] => 7908
                    [col2] => 7276
                )

            [1] => Array
                (
                    [id] => 238
                    [col1] => 9049
                    [col2] => 7276
                )

        )

    [Itm04] => Array
        (
            [0] => Array
                (
                    [id] => 82
                    [col1] => 8217
                    [col2] => 8217
                )

        )

)

但我希望索引为“Itm02”的项目作为第一个项目，因为它有更多项目。老实说，我想要和这个线程一样的东西。但是当我这样做时，

$warehouses = uksort($warehouses, function($a, $b) { return count($b) - count($a); });

但它返回一个空数组。如果有人可以提供帮助，那就太好了。

标签： phparrayssorting

Answer 1

uksort()返回一个布尔值。

尝试以下操作：

uksort($warehouses, function($a, $b) { return count($b) - count($a); });

print_r($warehouses);