php数组合并，id相同就求和

[mengfk000]

$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'=>4)
);
想合并成这种数组
$b = 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)
); //id=1的amount相加了1+3
该怎么做呢

[蜗牛慢慢向上爬]

1加4等于4吗？ 二重循环做 还有简单的，等楼下

[xuzuning]

$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);

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
        )

)

[mengfk000]

引用 1 楼 A9925 的回复:

1加4等于4吗？ 二重循环做 还有简单的，等楼下

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