php数组的统计解决办法

php数组的统计
我有这样的一个数组，不知道怎么来统计，A\B\c的分数
Array
(
[0] => Array
(
[0] => A
[1] => A因素
[2] => 1 //A因数的分数
)

[1] => Array
(
[0] => A
[1] => A因素
[2] => 3
)

[2] => Array
(
[0] => A
[1] => A因素
[2] => 6
)

[3] => Array
(
[0] => A
[1] => A因素
[2] => 6
)

[4] => Array
(
[0] => A
[1] => A因素
[2] => 1
)

[5] => Array
(
[0] => B
[1] => B因素
[2] => 1
)

[6] => Array
(
[0] => B
[1] => B因素
[2] => 2
)

[7] => Array
(
[0] => B
[1] => B因素
[2] => 3
)

[8] => Array
(
[0] => B
[1] => B因素
[2] => 1
)

[9] => Array
(
[0] => C
[1] => C因素
[2] => 1
)

[10] => Array
(
[0] => C
[1] => C因素
[2] => 5
)

)


------解决方案--------------------

PHP code

$ar = array(
    array('A','A因素',1),
    array('A','A因素',3),
    array('A','A因素',6),
    array('A','A因素',6),
    array('A','A因素',1),
    array('B','B因素',1),
    array('B','B因素',2),
    array('B','B因素',3),
    array('B','B因素',1),
    array('C','C因素',1),
    array('C','C因素',5)
);

$result = array();
foreach($ar as $v) {
    if (array_key_exists($v[0], $result)) $result[$v[0]] += $v[2];
    else $result[$v[0]] = $v[2];
}
print_r($result);