60 lines
1.0 KiB
Markdown
60 lines
1.0 KiB
Markdown
---
|
||
title: "JavaScript 创建并初始化任意长度的数组"
|
||
date: 2025-02-11T20:45:30Z
|
||
lastmod: 2025-02-20T22:59:05Z
|
||
tags: [JavaScript,Web 前端]
|
||
---
|
||
|
||
# JavaScript 创建并初始化任意长度的数组
|
||
|
||
## 直接定义
|
||
|
||
```javascript
|
||
var arr = [0, 0, 0, 0, 0]; // [0, 0, 0, 0, 0]
|
||
```
|
||
|
||
## 使用 push() 方法
|
||
|
||
```javascript
|
||
var arr = [];
|
||
|
||
for (let i = 0; i < 5; i++) {
|
||
arr.push(0);
|
||
}
|
||
|
||
// [0, 0, 0, 0, 0]
|
||
```
|
||
|
||
## 使用 Array 构造函数和 fill() 方法
|
||
|
||
```javascript
|
||
var arr = new Array(5); // [empty × 5]
|
||
arr.fill(0); // [0, 0, 0, 0, 0]
|
||
```
|
||
|
||
## 使用 Array 构造函数和数组展开
|
||
|
||
```javascript
|
||
var arr = [...new Array(5)]; // [undefined x 5]
|
||
```
|
||
|
||
```javascript
|
||
var arr = [...new Array(5).keys()]; // [0, 1, 2, 3, 4]
|
||
```
|
||
|
||
## 使用 Array.from()
|
||
|
||
> `Array.from(arrayLike[, mapFn[, thisArg]])`
|
||
|
||
```javascript
|
||
var arr = Array.from({length: 5}); // [undefined x 5]
|
||
```
|
||
|
||
```javascript
|
||
var arr = Array.from({length: 5}, () => 0); // [0, 0, 0, 0, 0]
|
||
```
|
||
|
||
```javascript
|
||
var arr = Array.from({length: 5}, (v, i) => (i + 1)); // [1, 2, 3, 4, 5]
|
||
```
|