二维数组分组求和！！

php数组分组求和小技巧，拿走不谢~

$a = array(

  0=>array('id'=>1,'name'=>'a','amount'=>1),

  1=>array('id'=>2,'name'=>'b','amount'=>2),

  2=>array('id'=>3,'name'=>'c','amount'=>3),

  3=>array('id'=>1,'name'=>'a','amount'=>3)

);

$b = array();

foreach($a as $v) {

  if(isset($b[$v['id']])) $b[$v['id']]['amount'] += $v['amount'];

  else $b[$v['id']] = $v;

}

$b = array_values($b);

print_r($b);

 

结果就是：：

Array

(    

     [0] => Array

        (

            [id] => 1

            [name] => a

            [amount] => 4

        )

    [1] => Array

        (

            [id] => 2

            [name] => b

            [amount] => 2

        )

    [2] => Array

        (

            [id] => 3

            [name] => c

            [amount] => 3

        )

)