php - 如何对 3 维数组中的值求和 [英] php - how to sum a value from 3 dimensional array

问题描述

我有如下数据:

Array
(
    [1] => Array
        (
            [A] => Array
                (
                    [AA] => 3
                    [AB] => 5
                )

            [B] => Array
                (
                    [BA] => 2
                )

    [2] => Array
        (
            [C] => Array
                (
                    [CA] => 4
                )

            [D] => Array
                (
                    [DA] => 1
                    [DB] => 2
                )
        )

    [3] => Array
        (
            [E] => Array
                (
                    [EA] => 1
                    [EB] => 2
                    [EC] => 3
                )

            [F] => Array
                (
                    [FA] => 0
                    [FB] => 7
                    [FC] => 7
                )
)

我想对价值求和，这是我的期望:

I want to sum the value and this is my expectation :

Array(
    [1] => 10        
    [2] => 7
    [3] => 20
)

这是我用来对值求和的代码:

Here is my code that I used for summing the value :

$total[$country_id][$province_id][$city_id] = $amount;

$result = array();
foreach( $total as $key => $val ){
         $total[$key] = array_sum ( $val );
}

有人可以解释我的代码有什么问题或解释 foreach 是如何工作的吗?因为我的代码的结果是 0，实际上我只研究了大约 1 周的 foreach.谢谢

can someone explain what is wrong with my code or explain how foreach work? because the result of my code is 0 and actually I just studied around 1 week about foreach. Thanks

推荐答案

如果你想了解更多关于 foreach 的信息，这里有一个更详细的解决方案:

As you want to know more about foreach, here is a more verbose solution using it :

$total = 0;
$totalByCountry = [];

// iterate over each country
foreach ($arr as $countryId => $provinces) {

    $totalByCountry[$countryId] = 0;

    // iterate over each province
    foreach ($provinces as $provinceId => $cities) {

        // iterate over each city
        foreach ($cities as $cityId => $value) {
            $totalByCountry[$countryId] += $value;
            $total += $value;
        }
    }
}

var_dump(totalByCountry) 的结果:

array (size=3)
    1 => int 10
    2 => int 7
    3 => int 20

var_dump($total) 的结果:

int 37

-- 编辑 --

在现实世界的项目中，你最好不要那么冗长，并使用为这种情况制作的 php 函数，例如 array_walk_recursive()，如 Philipp Maurer 和 Firoz Ahmad 答案.

In real world project, you better be less verbose and use php functions made for this kind of situation like array_walk_recursive(), as in Philipp Maurer and Firoz Ahmad answers.

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