javascript
复制代码
<script>
let arr=[1,2,3,4,5,4,3,2,1];
//1.数组去重
let result0=[...new Set(arr)];
console.log(`数组去重${result0}`);
//2.交集
let arr2=[4,5,6,5,6];
let result=[...new Set(arr)].filter(item=>{
let s2=new Set(arr2);//4 5 6
if(s2.has(item)){
return true;
}else{
return false;
}
})
console.log(`交集${result}`);
let result2=[...new Set(arr)].filter(item=>new Set(arr2).has(item));
console.log(`交集${result2}`);
//3.并集
let union=[...new Set([...arr,...arr2])];
console.log(`并集${union}`);
//4.差集
let diff=[...new Set(arr)].filter(item=> !(new Set(arr2).has(item)));
console.log(`并集${diff}`);
</script>
