# 章序号/节序号/节/笔记序号
codecademy,array
# 概念阐释
- 数组中的数组
- 可以通过**index**值来访问一组数组
- 继续写的数组是数组中的index，可以访问数组中的值
# 举例子
```js
const nestedArr = [[1], [2, 3]];
console.log(nestedArr[1]); // Output: [2, 3]
console.log(nestedArr[1][0]); // Output: 2，[0]的意思是[2,3]中的index0
```
- 第一个console访问的是第二组数组
- 第二个console访问的是第二组数组中的第一个值
# 类比、比较与对比
# 问题
**1.**
Let’s make a nested array! Create a variable `numberClusters`. Assign as its value an array with three array elements.
- The first array element should hold the elements `1` and `2` in that order.
- The second array element should hold the elements `3` and `4` in that order.
- The third array element should hold the elements `5` and `6` in that order.
**2.**
Awesome, you made a nested array! Now declare a variable named `target` using the `const` keyword and assign to access the element `6` inside `numberClusters`.
# 问题答案
```js
let numberClusters = [[1,2],[3,4],[5,6]];
const target = numberClusters[2][1];
console.log(target);
```
# 备注（经验集/错误集）
## 经验集
## 错误集
- 访问内嵌array时没有逗号。
## 参考资料