for 循环内的拼接返回错误值 JAVASCRIPT答案

【问题标题】：splice inside for loop return wrong values JAVASCRIPTfor 循环内的拼接返回错误值 JAVASCRIPT
【发布时间】：2021-06-25 03:09:35
【问题描述】：

我想将我的数组的内容分成 4 份，为此我首先需要知道每个分割数组集的内容是什么，我为此使用 Math.ceil。

results = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']; #lenght is 8
let half = Math.ceil(results.length / 4) # half is 2
let whole = [] #i want to insert the spliced value into this array
let j = 0;
let x
for (i = 0; i < 4; i++) {
    console.log("j:" + j)
    console.log("half: " + half)
    x = results.splice(j, half)
    console.log(x)
    j = j + half;
}

这是我的错误输出：

j:0
half: 2
[ 'a', 'b' ] #this is correct
j:2
half: 2
[ 'e', 'f' ] #this is wrong, it should be ['c','d']
j:4
half: 2
[] #this is wrong, should be ['e','d']
j:6
half: 2
[]#also wrong, should be ['f','g',]

当我在 for 循环之外测试它时，它工作正常，使用索引 0,2 - 2,2 - 4, 2 -6,2。可能是什么错误？

【问题讨论】：

标签： javascript splice

【解决方案1】：

Splice 方法更改数组的内容（通过删除、替换或添加）。你应该使用slice，结尾是i * 2 + half

results = ["a", "b", "c", "d", "e", "f", "g", "h"]; // #lenght is 8
let half = Math.ceil(results.length / 4); // # half is 2
let whole = []; //#i want to insert the spliced value into this array
let j = 0;
let x;
for (i = 0; i < 4; i++) {

  // change the end so that it will take next 2 element pos dynamically
  const end = i * 2 + half;
  x = results.slice(j, end);
  j = j + half;
  whole.push(x);
}

console.log(whole);

【讨论】：