数组交集，并集，差集 #82
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const arr1 = [1, 2, 3, 4]
const arr2 = [1, 3, 5, 6, 7]
function Union () {
const args = [].slice.call(arguments)
const arrs = args.reduce((total,current) => {
return total.concat(current)
},[])
return [...new Set(arrs)]
}
console.log('------')
// 返回传入所有数组的并集
console.log(Union(arr1, arr2))
function intersections () {
let res
const args = [].slice.call(arguments).map(e => new Set(e))
args.slice(1).forEach(e => {
res = [...new Set([...args[0]].filter(x => e.has(x)))]
})
return res
}
console.log('------')
// 返回传入所有数组的交集
console.log(intersections(arr1, arr2, [3]))
function subtraction () {
const result = []
let res = []
const args = [].slice.call(arguments).map(e => new Set(e))
args.forEach((e, ei) => {
res = []
args.forEach((x, xi) => {
if (ei !== xi) {
res.push([...new Set([...e].filter(y => !x.has(y)))])
}
})
result.push(res)
})
return result
}
console.log('------')
// 返回传入的所有数组相对于其他数组的差集
console.log(subtraction(arr1, arr2, [9, 10, 11])) |
const arr1 = [1, 3, 5];
const arr2 = [2, 4, 5, 6];
// 1. 并集
const arr3 = [...new Set(arr1.concat(arr2))];
// 2. 交集
const set = new Set(arr1);
const res = [];
for (let i = 0; i < arr2.length; i++) {
if (set.has(arr2[i]) && res.indexOf(arr2[i]) === -1) {
res.push(arr2[i]);
}
}
console.log(res);
// 3. 差集 这里求的是除了交集之外的
const res2 = [...new Set(arr1.concat(arr2))];
for(let i = 0; i < res2.length; i++){
if(res.indexOf(res2[i])!== -1) res2.splice(i, 1);
}
console.log(res2); |
// 1. 并集
const res1 = [...new Set(arr1.concat(arr2))];
console.log(res1)
// 2. 交集
const set = new Set(arr1);
const res2 = [];
for (let i = 0; i < arr2.length; i++) {
if (set.has(arr2[i]) && !res2.includes(arr2[i])) {
res2.push(arr2[i]);
}
}
console.log(res2);
// 3. 差集 这里求的是除了交集之外的
const res3 = res1.filter(item => !res2.includes(item))
console.log(res3); |
|
let arr1 = [1,2,3] // 并集 解构+set+解构 // 交集 // 差集 arr1-arr2 |
let arr1 = [1, 2, 3, 4];
let arr2 = [3, 4, 5, 6];
// 并集
let union = [...new Set([...arr1,...arr2])];
console.log(union); // 输出：[1 ,2 ,3 ,4 ,5 ，6]
//交集
let intersection = arr1.filter(x => new Set(arr2).has(x));
console.log(intersection); // 输出：[3 ，4]
// 差集 (arr1 相对于 arr2 的差集)
let difference = arr1.filter(x => !new Set(arr2).has(x));
console.log(difference); // 输出：[1 ，2] |
|
const setA = new Set([1, 2, 3]); // 并集 // 交集 // 差集 |
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
</body>
<script>
let set1 = new Set([1, 2, 3, 4, 6]);
let set2 = new Set([2, 6, 9, 10]);
let union = set1.union(set2); //并集
let intersection = set1.intersection(set2); //交集
let difference = set1.difference(set2); // 差集1
let isSubsetOf = set1.isSubsetOf(set2);//set1是否为set2的补集
let isSupersetOf = set2.isSupersetOf(set1) //返回布尔值与上面的这个一致
console.log('并集:', union); // Set { 1, 2, 3, 4, 6, 9, 10 }
console.log('交集:', intersection); // Set { 2, 6 }
console.log('差集1:', difference); // Set { 1, 3, 4 }
console.log('set1是否为set2的补集:', isSubsetOf); // false
console.log('set2是否为set1的补集:', isSupersetOf); // true
// 以下是ES6 Set的API
// union(otherSet) // 并集
// intersection(otherSet) // 交集
// difference(otherSet) // 差集
// has(value) // 判断集合中是否有该值
// add(value) // 添加值
// delete(value) // 删除值
// clear()
</script>
</html> |
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