php的多个dim数组中具有相同键的总价值

Question

我有一个这样的数组:

$a = array(
    array('amount'=>10,'curr'=>'USD'),
    array('amount'=>20,'curr'=>'JPY'),
    array('amount'=>30,'curr'=>'BAT'),
    array('amount'=>50,'curr'=>'BAT'),
    array('amount'=>100,'curr'=>'USD')
    );

我想把所有相同货币的金额加起来，然后返回如下:

$total = array('BAT'=>80,
              'JPY'=>20,
              'USD'=>110
           )

Answer 1

$total = array();
foreach($a as $arr){
    if(!isset($total[$arr['curr']])){
        $total[$arr['curr']] = 0;
    }
    $total[$arr['curr']] += $arr['amount'];
}