数组示例：
[0] => array(3) { ["id"] => string(1 "1" ["name"] => string(4) "jhon" ["amount"] => string(3) "850" } [1] => array(3) { ["id"] => string(1) "2" ["name"] => string(5) "david" ["amount"] => string(4) "1200" } [2] => array(3) { ["id"] => string(1) "3" ["name"] => string(4) "lucy" ["amount"] => string(3) "200" }需求说明：计算数组中所有元素的 amount 项的和。
方法一：
$total = array_sum(array_map(function($val){return $val['amount'];}, $arr));方法二：
$total = 0; foreach($arr as $item){ $total += (int) $item['amount']; }声明：本文为原创文章，版权归主机之家测评所有，欢迎分享本文，转载请保留出处！
