Set-使用方法及特性

Set是ES6中新增的类型，和数组类似，唯一不同在于该类型不会有重复的数据，一般常用来对数组去重****以下几个set常用方法

let set1 = new Set([1, 2, 2, 3, 4, 3, 5]) console.log('distinct 1:', set1)

结果：distinct 1: { 1, 2, 3, 4, 5 }

let arr1 = [1, 2, 3, 4] let arr2 = [2, 3, 4, 5, 6] let set2 = new Set([...arr1, ...arr2]) console.log('distinct 2:', set2)

结果：distinct 2: { 1, 2, 3, 4, 5, 6 }

set给数组去重以后得到的结果不是数组结构 , 需要转换成数组 , 方法如下 :

let set3 = new Set([4, 5, 6]) console.log('set to array 1:',[...set3])   // 解构赋值 console.log('set to array 2:', Array.from(set3))

结果：

set to array 1: [ 4, 5, 6 ] set to array 2: [ 4, 5, 6 ]

let set2 = new Set([4,5,6]) console.log('array to set 1:', set2)

let set3 = new Set(new Array(7, 8, 9)) console.log('array to set 2:', set3)

结果：

array to set 1: Set { 4, 5, 6 } array to set 2: Set { 7, 8, 9 }