PHP 根據key 給二維數組分組

咱們常常拿到一個二維數組出來，會發現結果和本身想要的有些誤差，可能須要根據二維數組裏的某個字段對數組分組。
先來看如下數組，

Array
(
    [0] => Array
        (
            [id] => 1
            [wo_id] => 2
            [evaluate_id] => 1
            [type] => 分組1
            [ctime] => 2016-12-02 11:39:34
        )

    [1] => Array
        (
            [id] => 2
            [wo_id] => 31
            [evaluate_id] => 2
            [type] => 分組1
            [ctime] => 2016-12-12 11:39:50
        )

    [2] => Array
        (
            [id] => 3
            [wo_id] => 31
            [evaluate_id] => 4
            [type] => 分組2
            [ctime] => 2016-12-02 11:40:01
        )

    [3] => Array
        (
            [id] => 4
            [wo_id] => 2
            [evaluate_id] => 5
            [type] => 分組2
            [ctime] => 2016-12-07 10:21:40
        )

    [4] => Array
        (
            [id] => 5
            [wo_id] => 2
            [evaluate_id] => 3
            [type] => 分組2
            [ctime] => 2016-12-07 10:21:51
        )

    [5] => Array
        (
            [id] => 6
            [wo_id] => 2
            [evaluate_id] => 2
            [type] => 分組3
            [ctime] => 2016-12-07 10:21:56
        )

    [6] => Array
        (
            [id] => 7
            [wo_id] => 4
            [evaluate_id] => 2
            [type] => 分組3
            [ctime] => 2016-12-07 10:22:10
        )
)    

這裏是一個很典型的例子，若是我但願把 數組中的數據 根據 type（分組） 分開處理，若是不分組，可能循環上會很是冗餘，因此有了下面的一個分組函數：

　　public static function array_group_by($arr, $key)
    {
        $grouped = [];
        foreach ($arr as $value) {
            $grouped[$value[$key]][] = $value;
        }
        // Recursively build a nested grouping if more parameters are supplied
        // Each grouped array value is grouped according to the next sequential key
        if (func_num_args() > 2) {
            $args = func_get_args();
            foreach ($grouped as $key => $value) {
                $parms = array_merge([$value], array_slice($args, 2, func_num_args()));
                $grouped[$key] = call_user_func_array('array_group_by', $parms);
            }
        }
        return $grouped;
    }

$arr : 二維數組

$key: 須要分組的key

獲得的結果是：

Array
(
    [分組2] => Array
        (
            [0] => Array
                (
                    [id] => 1
                    [wo_id] => 2
                    [evaluate_id] => 1
                    [ctime] => 2016-12-02 11:39:34
                    [type] => 分組2
                )

            [1] => Array
                (
                    [id] => 2
                    [wo_id] => 31
                    [evaluate_id] => 2
                    [ctime] => 2016-12-12 11:39:50
                    [type] => 分組2
                )

            [2] => Array
                (
                    [id] => 3
                    [wo_id] => 31
                    [evaluate_id] => 4
                    [ctime] => 2016-12-02 11:40:01
                    [type] => 分組2
                )

        )

    [分組1] => Array
        (
            [0] => Array
                (
                    [id] => 4
                    [wo_id] => 2
                    [evaluate_id] => 5
                    [ctime] => 2016-12-07 10:21:40
                    [type] => 分組1
                )

            [1] => Array
                (
                    [id] => 5
                    [wo_id] => 2
                    [evaluate_id] => 3
                    [ctime] => 2016-12-07 10:21:51
                    [type] => 分組1
                )
        )
)