vue Set Map Array 基本用法

Set

1.添加

        let mySet = new Set();
        //添加
        mySet.add("a")
          .add("b")
          .add("a")
          .add("c")
        console.log("add:", mySet)

2.删除

        //删除
        mySet.delete("a")
        console.log("delete:", mySet)

3.查找

        let contain = mySet.has("a")
        console.log("contains", contain)

4.遍历

        //遍历
        mySet.forEach(a => {
          console.log("forEach:", a)
        })

5.转换成数组

 let setGroup = [...mySet]
 console.log(setGroup)

6.清除

 //清除
  mySet.clear()

Map

1.添加

        let myMap = new Map()

        //添加
        myMap.set("a", "1")
          .set("b", "2")
          .set("c", "3")
        console.log("myMap:", myMap)

2.获取

        //获取
        let val = myMap.get("a")
        console.log("val", val)

3.是否存在某个值

        //是否存在
        let has = myMap.has('b')
        console.log("has", has)

4.删除

        //删除
        myMap.delete("a")
        console.log("delete", myMap)

5.keys

        for (let key of myMap.keys()) {
          console.log("key:", key)
        }

6.values

        //values
        for (let value of myMap.values()) {
          console.log("value", value)
        }

7.遍历

        //遍历
        myMap.forEach((value, key) => {
          console.log("value:" + value, "key:" + key)
        })

8.合并

        //合并
        let myMap2 = new Map()
        myMap2.set("d", "5")
            .set("e", 6)
        let merge = new Map([...myMap, ...myMap2])
        console.log("merge:", merge)

9.转换成数组

        //转换成数组
        let mapToArray = [...myMap]
        console.log("mapToArray", mapToArray)
        let keyArray = [...myMap.keys()]
        console.log("keyArray", keyArray)
        let valueArray = [...myMap.values()]
        console.log("valueArray", valueArray)

Array

1.生成

        //添加
        let arr = new Array()
        arr.push("1")
        arr.push("2")
        arr.push("3")
        arr.push("4")
        arr.push("4")
        console.log("arr", arr)
        let arr2 = ["5", "6", "7"]
        console.log("arr2", arr2)

        //填充
        let arr3 = new Array(5)
        arr3.fill(1)
        console.log("arr3", arr3)

2.删除

        //删除第一个元素
        let del = arr.splice(0, 1)
        console.log("del", del)

        //删除最后一个
        let pop = arr.pop()
        console.log("pop", pop)

3.查找

        //查找第一个,返回下标
        let idx = arr.indexOf("3")
        console.log("idx:", idx)
        //查找最后一个，返回下标
        let lastIdx = arr.lastIndexOf("4")
        console.log("lastIdx:", lastIdx)
        //查找返回元素
        let find = arr.find(a => a == "3")
        console.log("find", find)

        //包含
        let cont = arr.includes("4")
        console.log("contains:", cont)

4.拼接字符串

        //拼接成字符串
        let mergeStr = arr.join(" ")
        console.log("merge:", mergeStr)

5.过滤

        //过滤
        let filer = arr.filter(a => a != "4")
        console.log("filter:", filer)

6.合并

        //两个数组合并
        let mergeArr = arr.concat(arr2)
        console.log("mergeArr", mergeArr)
        let mergeArr2 = [...arr, ...arr2]
        console.log("mergeArr2", mergeArr2)

7.转换

        //转换
        let objArr = [
          {'name': '小明', 'age': 10},
          {'name': '小红', 'age': 9}
        ]
        let convert = objArr.map(a => a.name)
        console.log("conver", convert) //["小明", "小红"]

8.规约

        //规约
        let sum = objArr.reduce((a, b) => a.age + b.age)
        console.log("sum:", sum)     //19

9.反转

        //反转
        let reverse = arr.reverse()
        console.log("reverse:", reverse)

10.截取

        //截取
        let slice = arr.slice(2, 3)
        console.log("slice:", slice)

11.排序

        //排序
        let sort = arr.sort((a, b) => a - b)
        console.log("sort:",sort)

《中医基础理论》