【set用法之去重交集、并集、差集】

m0_53679993

于 2022-04-27 15:13:23 发布

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文章标签： css javascript html jquery es6

本文链接：https://blog.youkuaiyun.com/m0_53679993/article/details/124451315

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本文介绍了如何使用JavaScript对数组进行去重、计算交集、并集和差集，通过实例展示了如何使用Set和filter方法实现这些操作。

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1.数组去重

arr中有相同的数去掉

let arr = [1,2,3,4,5,4,3,2,1];
let result = [...new Set(arr)];
console.log(result);//1,2,3,4,5

2.交集

let arr = [1,2,3,4,5,4,3,2,1];
let arr2 = [4,5,6,5,6];
let result =[...new Set(arr)].filter(item => { 
    let s2=new Set(arr2);//[4·5.6]
    if(s2.has(item)){
        return true;
    }else{
        return false;
    }
});
//let result =[...new Set(arr)].filter(item => new Set(arr2).has(item)); 
console.log(result);//[4,5]

3.并集

let arr = [1,2,3,4,5,4,3,2,1];
let arr2 = [4,5,6,5,6];
let union=[...new Set([...arr,...arr2])];
console.log(union)//[1,2,3,4,5,6]

4.差集

let arr = [1,2,3,4,5,4,3,2,1];
let arr2 = [4,5,6,5,6];
let diff=[...new Set(arr)].filter(item=>!(new Set(arr2).has(item)));
console.log(diff)//[1,2,3]