JavaScript：麻烦减少

Question

我正在尝试获取较大组中一个数组的总和。 代码更新了第一个数组中的第一个数组值，但是reduce函数不起作用。 这是代码：

JavaScript（查看结果的HTML）：

 var boughtRaw = [[0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]; var boughtCalc = function (level) { boughtRaw[0[0]] = 5 var Raw = boughtRaw[level]; window["boughtList" + level] = Raw.reduce(function(a, b) { return a + b;}, 0); }; boughtCalc(0); document.getElementById("debug").innerHTML = boughtList0; /* Should return 5 */ 

 <span id="debug" style="border: 1px dashed red">Debug</span> 

Answer 1

您必须在此行boughtRaw[0][0] = 5 boughtRaw[0[0]] = 5 boughtRaw[0][0] = 5为boughtRaw[0][0] = 5 。

 var boughtRaw = [[0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]; var boughtCalc = function (level) { boughtRaw[0][0] = 5; // corrected var Raw = boughtRaw[level]; window["boughtList" + level] = Raw.reduce(function(a, b) { return a + b;}, 0); }; boughtCalc(0); document.getElementById("debug").innerHTML = boughtList0; /* return 5 */ 

 <span id="debug" style="border: 1px dashed red">Debug</span> 

---

要访问数组（数组.. of数组）的元素，必须将[]...[]彼此相邻放置 ，而不是像[[...[]]] 。

var element1 = array[0] // get first element of array
var element2 = element1[0] // get first element of element1 
.....
var result = elementN[0] // get first element of elementN

可以替换为

var result = array[0][0]...[0].