标签：include elements 不可 set html tag includes 遍历 pre
1. Set容器 : 无序不可重复的多个value的集合体
* Set()
* Set(array)
* add(value)
* delete(value)
* has(value)
* clear()
* size
2. Map容器 : 无序的 key不重复的多个key-value的集合体
* Map()
* Map(array)
* set(key, value)//添加
* get(key)
* delete(key)
* has(key)
* clear()
* size
let set = new Set([1,2,3,4,3,2,1,6]); console.log(set); set.add(‘abc‘); console.log(set, set.size); //delete(value) set.delete(2); console.log(set); //has(value) console.log(set.has(2));//false console.log(set.has(1));//true //clear() set.clear(); console.log(set); let map = new Map([[‘abc‘, 12],[25, ‘age‘]]); console.log(map); map.set(‘男‘, ‘性别‘); console.log(map); console.log(map.get(25));//age //delete(key) map.delete(‘男‘); console.log(map); console.log(map.has(‘男‘));//false console.log(map.has(‘abc‘));//true map.clear(); console.log(map);
3：for of循环
for(let value of target){}循环遍历
1. 遍历数组
2. 遍历Set
3. 遍历Map
4. 遍历字符串
5. 遍历伪数组
let arr = [1,2,3,4,5];
for(let num of arr){
console.log(num);
}
let set = new Set([1,2,3,4,5]);
for(let num of set){
console.log(num);
}
let str = ‘abcdefg‘;
for(let num of str){
console.log(num);
}
let btns = document.getElementsByTagName(‘button‘);
for(let btn of btns){
console.log(btn.innerHTML);
}
4：
1. 指数运算符(幂): **
2. Array.prototype.includes(value) : 判断数组中是否包含指定value
标签：include elements 不可 set html tag includes 遍历 pre
原文地址：https://www.cnblogs.com/love-life-insist/p/9938800.html
