如何将数组数组中相同索引处的元素加到一个数组中？ [英] How to sum elements at the same index in array of arrays into a single array?

问题描述

假设我有一个数组数组，如下所示：

Let's say that I have an array of arrays, like so:

[
  [0, 1, 3],
  [2, 4, 6],
  [5, 5, 7],
  [10, 0, 3]
]

如何生成一个新数组，该数组在javascript中对内部数组的每个位置的所有值求和？在这种情况下，结果将是：[17,19,19]。无论内部数组的长度如何，我都需要能够提供一个有效的解决方案。我认为这可以使用map和for-of的一些组合，或者可能减少，但我不能完全围绕它。我已经搜索但找不到任何与此匹配的例子。

How do I generate a new array that sums all of the values at each position of the inner arrays in javascript? In this case, the result would be: [17, 10, 19]. I need to be able to have a solution that works regardless of the length of the inner arrays. I think that this is possible using some combination of map and for-of, or possibly reduce, but I can't quite wrap my head around it. I've searched but can't find any examples that quite match this one.

推荐答案

你可以使用 Array.prototype.reduce（） 与 Array.prototype.forEach（） 。

You can use Array.prototype.reduce() in combination with Array.prototype.forEach().

var array = [
        [0, 1, 3],
        [2, 4, 6],
        [5, 5, 7],
        [10, 0, 3]
    ],
    result = array.reduce(function (r, a) {
        a.forEach(function (b, i) {
            r[i] = (r[i] || 0) + b;
        });
        return r;
    }, []);
document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');

更新，通过采用减少数组的地图来缩短方法。

Update, a shorter approach by taking a map for reducing the array.

var array = [[0, 1, 3], [2, 4, 6], [5, 5, 7], [10, 0, 3]],
    result = array.reduce((r, a) => a.map((b, i) => (r[i] || 0) + b), []);
    
console.log(result);

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