js数组方法
2022/2/20 23:56:23
本文主要是介绍js数组方法,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!
es6为Array类增加了@@iterator属性,需要通过Sysbol.iterator来访问
let number = [1, 2, 3] let iterator = number[Symbol.iterator]() console.log(iterator.next())//{value: 1, done: false} console.log(iterator.next())//{value: 2, done: false} console.log(iterator.next())//{value: 3, done: false} console.log(iterator.next())//{value: undefined, done: true}
一旦没有可迭代的值,iterator.next()就会返回value为undefoned,done为true的对象
enteries方法返回包含键值对的@@iterator
let number = [5, 4, 3] let iterator = number.entries()//得到键值对的迭代器 console.log(iterator.next().value)//[0, 5],位置为0的值为5 console.log(iterator.next())//{value: Array(2), done: false} console.log(iterator.next())//{value: Array(2), done: false} console.log(iterator.next())//{value: undefined, done: true}
keys方法返回包含数组索引的@@iterator
let number = [5, 4, 3] let iterator = number.keys() console.log(iterator.next())//{value: 0, done: false} console.log(iterator.next())//{value: 1, done: false} console.log(iterator.next())//{value: 2, done: false} console.log(iterator.next())//{value: undefined, done: true}
values方法返回包含数组的值的@@iterator
let number = [5, 4, 3] let iterator = number.values() console.log(iterator.next())//{value: 5, done: false} console.log(iterator.next())//{value: 4, done: false} console.log(iterator.next())//{value: 3, done: false} console.log(iterator.next())//{value: undefined, done: true}
Array.from(array) 根据已有的数组创建一个新数组
```javascript
console.log( Array.from([1,2,3]))//[1, 2, 3]
```
==Array.of(params)==根据传入的参数创建一个新数组
console.log(Array.of(2,5,6))//[2, 5, 6]
push()
unshift()
pop()
shift()
splice()
concat()
迭代器函数:
- every()
- some()
- forEach()
- map()
- filter()
- reduce()
for……of
@@iterator
entries()
keys()
values()
Array.from()
Array.of()
fill()
copyWithin()
reverse()
sort()
indexOf()
lastIndexOf()
find()
findIndex()
includes()
toString()
join()
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