php数据优化

Array
(
    [0] => Array
        (
            [id] => 19
            [receive_id] => 41
            [mac] => a4:3d:78:fc:49:50
            [staytime] => 400
        )

    [1] => Array
        (
            [id] => 20
            [receive_id] => 42
            [mac] => a4:3d:78:fc:49:51
            [staytime] => 200
        )

    [2] => Array
        (
            [id] => 22
            [receive_id] => 42
            [mac] => a4:3d:78:fc:49:50
            [staytime] => 2443
        )

    [3] => Array
        (
            [id] => 23
            [receive_id] => 42
            [mac] => a4:3d:78:fc:49:50
            [staytime] => 1443
        )

    [4] => Array
        (
            [id] => 24
            [receive_id] => 42
            [mac] => a4:3d:78:fc:49:51
            [staytime] => 1143
        )

    [5] => Array
        (
            [id] => 25
            [receive_id] => 42
            [mac] => a4:3d:78:fc:49:51
            [staytime] => 543
        )

)
举例将以上数组按mac区分成

Array
(
    [a4:3d:78:fc:49:50] => Array
        (
            [id] => 19
            [receive_id] => 41
            [mac] => a4:3d:78:fc:49:50
            [staytime] => 400
            [timmarr] => Array
                (
                    [0] => Array
                        (
                            [id] => 19
                            [receive_id] => 41
                            [mac] => a4:3d:78:fc:49:50
                            [staytime] => 400
                        )

                    [1] => Array
                        (
                            [id] => 22
                            [receive_id] => 42
                            [mac] => a4:3d:78:fc:49:50
                            [staytime] => 2443
                        )

                    [2] => Array
                        (
                            [id] => 23
                            [receive_id] => 42
                            [mac] => a4:3d:78:fc:49:50
                            [staytime] => 1443
                        )

                )

        )

    [a4:3d:78:fc:49:51] => Array
        (
            [id] => 20
            [receive_id] => 42
            [mac] => a4:3d:78:fc:49:51
            [staytime] => 200
            [timmarr] => Array
                (
                    [0] => Array
                        (
                            [id] => 20
                            [receive_id] => 42
                            [mac] => a4:3d:78:fc:49:51
                            [staytime] => 200
                        )

                    [1] => Array
                        (
                            [id] => 24
                            [receive_id] => 42
                            [mac] => a4:3d:78:fc:49:51
                            [staytime] => 1143
                        )

                    [2] => Array
                        (
                            [id] => 25
                            [receive_id] => 42
                            [mac] => a4:3d:78:fc:49:51
                            [staytime] => 543
                        )

                )

        )

)
----------------------
php代码：

$macArr =   [];
$macUserArr =    [];

for($i=0;$i<$countList;$i++){
    if(!in_array($list[$i]['mac'],$macArr)){
        $macArr[]   =   $list[$i]['mac'];
        $macUserArr[$list[$i]['mac']] =   $list[$i];
        $macUserArr[$list[$i]['mac']]['timmarr'][]  = $list[$i];
    }else{
        $macUserArr[$list[$i]['mac']]['timmarr'][]  =   $list[$i];
    }
}
少循环次数