在控制台中获取数组值答案

【问题标题】：getting array value in console在控制台中获取数组值
【发布时间】：2021-08-30 09:20:46
【问题描述】：

我有一个包含数组的数组 (tot)。我需要检查 (tot) 中的每个条目是否有值，这是通过在控制台输入 AA[3] 来完成的，但是，当我从脚本执行它时，AA[3] 不会返回任何值！

这是我的脚本：

tot=["AA","AB","AC"];
AA=["1","2","3","4","5","6","7"];
AB=["1","2","3","4","5","6","7"];
AC=["1","2","3","4","5","6","7"];

for (let i = 0; i < tot.length; i++)  
{
tot[i]+'[2]';
}

【问题讨论】：

“Variable” variables in JavaScript
你想用这个值做什么？您的循环不会返回或分配任何内容。
我需要在 tot 中显示每个值，然后显示一个设置值来检查它是否有，比如我需要位置 5，我在控制台中输入 AA[5]，我要么得到一个值，要么未定义，所以我需要在 tot 下测试每个 5、AA[5]、AC[5] 等等

标签： javascript arrays console

【解决方案1】：

我有一个数组（tot），里面有数组

实际上，这是不准确的。您有一个数组，其中包含不是数组的字符串值。数组中的字符串值与某些数组的名称相匹配。取而代之的是，您可能想使用数组对象，例如：

let AA=["1","2","3","4","5","6","7"];
let AB=["1","2","3","4","5","6","7"];
let AC=["1","2","3","4","5","6","7"];
let tot={AA,AB,AC};
let index = 5;

for (let key in tot) {
    console.log(`${key}[${index}]: ${tot[key][index]}`);
}

【讨论】：

【解决方案2】：

你可以试试：

const tot = [
    ["1","2","3","4","5","6","7"],
    ["1","2","3","4","5","6","7"],
    ["1","2","3","4","5","6","7"]
];

for (let i = 0; i < tot.length; i++)  
{
    console.log(tot[i][2]);
}

【讨论】：

【解决方案3】：

变量不能作为函数工作。不要在循环中写变量，试试：

console.log(tot);

另外，我假设你打算这样做 var tot = new Array(AA, AB, AC);

var AA=["1","2","3","4","5","6","7"];
var AB=["1","2","3","4","5","6","7"];
var AC=["1","2","3","4","5","6","7"];
var tot= new Array(AA,AB,AC);

for (let i = 0; i < tot.length; i++)  
{
tot[i].push("2")
console.log(tot[i]);
}

【讨论】：

【解决方案4】：

要遍历tot数组中的每个数组，你必须嵌套两个for循环，并且console.log嵌套for循环中的每个值：


const AA=["1","2","3","4","5","6","7"];
const AB=["1","2","3","4","5","6","7"];
const AC=["1","2","3","4","5","6","7"];
const tot=[AA,AB,AC];

const logArray = (tot) => {
  for (let i = 0; i < tot.length; i++) {
    console.warn(`tot[${i}] contains:`);
    for (let j = 0; j < tot[i].length; j++) {
      console.log(tot[i][j]);
    }
  }
};

【讨论】：

【解决方案5】：

您的代码没有输出任何内容，因为您没有要求它这样做。还有那行： tot[i] + '[2]' 不正确。你到底想在那里做什么。我将其更改为向每个元素添加 '[2]' 字符串，但似乎这不是您想要的。

tot=["AA","AB","AC"];
AA=["1","2","3","4","5","6","7"];
AB=["1","2","3","4","5","6","7"];
AC=["1","2","3","4","5","6","7"];

for (let i = 0; i < tot.length; i++)  
{
tot[i]+='[2]';
}
console.log(tot)

【讨论】：