JS数组操作

1、数组交集

①普通数组

const arr1 = [1, 2, 3, 4, 5 , 8 ,9],arr2 = [5, 6, 7, 8, 9];

const intersection = arr1.filter(function (val) { return arr2.indexOf(val) > -1 })

console.log(intersection) //[5, 8, 9]

②数组对象

const arr1 = [{ name: 'name1', id: 1 }, { name: 'name2', id: 2 }, { name: 'name3', id: 3 }, { name: 'name5', id: 5 }];

const arr2 = [{ name: 'name1', id: 1 }, { name: 'name2', id: 2 }, { name: 'name3', id: 3 }, { name: 'name4', id: 4 }, { name: 'name5', id: 5 }];

const result = arr2.filter(function (v) {

  return arr1.some(n => JSON.stringify(n) === JSON.stringify(v))

})

console.log(result); // [{ name: 'name1', id: 1 },{ name: 'name2', id: 2 },{ name: 'name3', id: 3 },{ name: 'name5', id: 5 }]

2.数组并集

①普通数组

const arr1 = [1, 2, 3, 4, 5, 8, 9]

const arr2 = [5, 6, 7, 8, 9];

const result = arr1.concat(arr2.filter(v => !arr1.includes(v)))

console.log(result) //[1, 2, 3, 4,5, 8, 9]

②数组对象

const arr1 = [{ name: 'name1', id: 1 }, { name: 'name2', id: 2 }, { name: 'name3', id: 3 }];

const arr2 = [{ name: 'name1', id: 1 }, { name: 'name4', id: 4 }, { name: 'name5', id: 5 }];

let arr3 = arr1.concat(arr2);

let result = [];

let obj = [];

result = arr3.reduce(function (prev, cur, index, arr) {

  obj[cur.id] ? '' : obj[cur.id] = true && prev.push(cur);

  return prev;

}, []);

console.log(result); //[{ name: 'name1', id: 1 },{ name: 'name2', id: 2 },{ name: 'name3', id: 3 },{ name: 'name4', id: 4 },{ name: 'name5', id: 5 }]

3.数组差集

①普通数组

const arr1 = [1, 2, 3, 4, 5, 8, 9]

const arr2 = [5, 6, 7, 8, 9];

const diff = arr1.filter(item => !new Set(arr2).has(item))

console.log(diff) //[ 1, 2, 3, 4 ]

②数组对象

let arr1 = [{ name: 'name1', id: 1 }, { name: 'name2', id: 2 }, { name: 'name3', id: 3 }];

let arr2 = [{ name: 'name1', id: 1 }, { name: 'name4', id: 4 }, { name: 'name5', id: 5 }];

let result = arr1.filter(function (v) {

  return arr2.every(n => JSON.stringify(n) !== JSON.stringify(v))

})

console.log(result); // [ { name: 'name2', id: 2 }, { name: 'name3', id: 3 } ]

4.数组补集

①普通数组

const arr1 = [1, 2, 3, 4, 5, 8, 9]

const arr2 = [5, 6, 7, 8, 9];

const difference = Array.from(new Set(arr1.concat(arr2).filter(v => !new Set(arr1).has(v) || !new Set(arr2).has(v))))

console.log(difference) //[ 1, 2, 3, 4, 6, 7 ]

②数组对象

let arr1 = [{ name: 'name1', id: 1 }, { name: 'name2', id: 2 }, { name: 'name3', id: 3 }];

let arr2 = [{ name: 'name1', id: 1 }, { name: 'name4', id: 4 }, { name: 'name5', id: 5 }];

let arr3 = arr1.concat(arr2);

let result = arr3.filter(function (v) {

  return arr1.every(n => JSON.stringify(n) !== JSON.stringify(v)) || arr2.every(n => JSON.stringify(n) !== JSON.stringify(v))

})

console.log(result); // [{ name: 'name2', id: 2 },{ name: 'name3', id: 3 },{ name: 'name4', id: 4 },{ name: 'name5', id: 5 }]

5.数组去重

①普通数组

console.log(Array.from(new Set([1, 2, 3, 3, 4, 4]))) //[1,2,3,4]

console.log([...new Set([1, 2, 3, 3, 4, 4])]) //[1,2,3,4]

②数组对象

const arr = [{ name: 'name1', id: 1 }, { name: 'name2', id: 2 }, { name: 'name3', id: 3 }, { name: 'name1', id: 1 }, { name: 'name4', id: 4 }, { name: 'name5', id: 5 }];

const obj = [];

const result = arr.reduce(function (prev, cur, index, arr) {

  obj[cur.id] ? '' : obj[cur.id] = true && prev.push(cur);

  return prev;

}, []);

console.log(result) //[{ name: 'name1', id: 1 },{ name: 'name2', id: 2 },{ name: 'name3', id: 3 },{ name: 'name4', id: 4 },{ name: 'name5', id: 5 }]

6.数组排序

①普通数组

console.log([1, 2, 3, 4].sort((a, b) => a - b)); // [1, 2,3,4] 升序

console.log([1, 2, 3, 4].sort((a, b) => b - a)); // [4,3,2,1] 降序

②数组对象

const arr1 = [{ name: "Rom", age: 12 }, { name: "Bob", age: 22 }].sort((a, b) => { return a.age - b.age })//升序

const arr2 = [{ name: "Rom", age: 12 }, { name: "Bob", age: 22 }].sort((a, b) => { return -a.age + b.age })//降序

console.log(arr2) // [{ name: 'Bob', age:22 }, { name: 'Rom', age: 12 }]

console.log(arr1) // [ { name: 'Rom', age: 12 }, { name: 'Bob', age: 22 } ]

7.数组合并

①普通数组

const arr1 =[1, 2, 3, 4].concat([5, 6]) //[1,2,3,4,5,6]

const arr2 =[...[1, 2, 3, 4],...[4, 5]] //[1,2,3,4,5,6]

const arrA = [1, 2], arrB = [3, 4]

const arr3 =Array.prototype.push.apply(arrA, arrB)//arrA值为[1,2,3,4]

②数组对象

const arr4 = [{ age: 1 }].concat([{ age: 2 }])

const arr5 = [...[{ age: 1 }],...[{ age: 2 }]]

console.log(arr4) //[ { age: 1 }, { age: 2 } ]

console.log(arr5) // [ { age: 1 }, { age: 2 } ]

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