二维数组依据键值相加

二维数组根据键值相加
怎样根据每一个数组的键值相加？


Array
(
    [0] => Array
        (
            [reg] => 0
            [regs] => 0
            [login] => 7
            [pay] => 0
            [buy] => 4
            [payment] => 11334.00
            [recharge] => 1
            [rechargea] => 3600.00
        )

    [1] => Array
        (
            [reg] => 1
            [regs] => 0
            [login] => 22
            [pay] => 0
            [buy] => 0
            [payment] => 0.00
            [recharge] => 0
            [rechargea] => 0.00
        )

    [2] => Array
        (
            [reg] => 0
            [regs] => 0
            [login] => 5
            [pay] => 0
            [buy] => 1
            [payment] => 376.00
            [recharge] => 0
            [rechargea] => 0.00
        )