Php 关联数组总值计数

检查下面的数组print_r（）视图。我只想得到“金额”值的总和。和输出不应在数组中。它应该是一个简单的整数值。所以结果应该是4+3+9=16

Array
    (
        [0] => Array
            (
                [id] => 15
                [portfolio_id] => 1
                [stock_id] => 1
                [amount] => 4
                [date] => 04/02/2017
                [created_at] => 2017-04-02 09:04:30
                [updated_at] => 2017-04-02 09:04:30
            )

        [1] => Array
            (
                [id] => 14
                [portfolio_id] => 1
                [stock_id] => 3
                [amount] => 3
                [date] => 04/02/2017
                [created_at] => 2017-04-02 09:03:40
                [updated_at] => 2017-04-02 09:03:40
            )

        [2] => Array
            (
                [id] => 13
                [portfolio_id] => 1
                [stock_id] => 4
                [amount] => 9
                [date] => 04/02/2017
                [created_at] => 2017-04-02 09:03:36
                [updated_at] => 2017-04-02 09:03:36
            )

    )

尝试

array\u sum（array\u列（$input，'amount'）

array\u列
将返回
amount
键和
array\u sum
计算返回数组中的值之和
尝试以下方法：

function sum($carry, $item)// summing on amount column of the inner array $item
{
    $carry += $item["amount"];
    return $carry;
}
echo "Amount sum : ".array_reduce($a, "sum");// output : 59

示例：


<?php
/**
 * Created by PhpStorm.
 * User: lenovo
 * Date: 4/2/2017
 * Time: 11:17 AM
 */

  $array = array
     (
        array("name"=>"Volvo","amount"=>22,"id"=>18),
        array("name"=>"BMW","amount"=>15,"id"=>13),
        array("name"=>"Saab","amount"=>5,"id"=>2),
        array("name"=>"Land Rover","amount"=>17,"id"=>15)
     );

    function sum($carry, $item)
    {
        $carry += $item["amount"];
        return $carry;
    }
    echo "Amount sum : " .array_reduce($array, "sum");// output : 59

<代码>总是考虑添加实况演示链接：它使你的代码更加清晰。