JavaScript：减少

Question

我试图在更大的组中获得一个数组的总和。代码更新第一个数组中的第一个数组值，但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

您必须将boughtRaw[0[0]] = 5更正为此行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（数组的数组）的元素，您必须将[]...[]放在彼此旁边，而不是像[[...[]]]那样。

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

可以用

代替

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