Array deduplication
Deduplication of object arrays is divided into two categories: deduplication based on a certain attribute, which is exactly the same object as deduplication (the attribute and attribute values are the same)
1. Array nested objects, deduplication based on a certain attribute of the object
let arr = [
{
id:1, setting:'demo', jointCategoryName:'success'},
{
id:2, setting:'dev', jointCategoryName:'success'},
{
id:3, setting:'prod', jointCategoryName:'fail'},
{
id:4, setting:'demo', jointCategoryName:'waiting'},
{
id:3, setting:'prod', jointCategoryName:'fail'},
{
id:2, setting:'test', jointCategoryName:'success'}
]
function unipFunc(arr){
let arr1 = []; //存id
let newArr = []; //存新数组
for(let i in arr){
if(arr1.indexOf(arr[i].id) == -1){
arr1.push(arr[i].id);
newArr.push(arr[i]);
}
}
return newArr;
}
2. Array nested objects, duplicate identical objects (property and attribute values are all the same)
The arrangement is as follows:
First, loop through the array to get an array composed of all properties of the object;
secondly, loop through the property array to splice the properties of the object and the corresponding values into a string;
then, use the hasOwnProperty method to determine whether the string is a property in the object obj, if not, use this string as a property, and add a new property to the obj object as a value of true;
let arr = [
{
id:1, setting:'demo', jointCategoryName:'success'},
{
id:2, setting:'dev', jointCategoryName:'success'},
{
id:3, setting:'prod', jointCategoryName:'fail'},
{
id:4, setting:'demo', jointCategoryName:'waiting'},
{
id:3, setting:'prod', jointCategoryName:'fail'},
{
id:2, setting:'test', jointCategoryName:'success'}
]
function unipFunc(arr){
var newArr= []; //存新数组
var obj= {
}; //存处理后转成字符串的对象
for (var i = 0; i < arr.length; i++) {
var keys = Object.keys(arr[i]);
//keys.sort(function(a, b) {
// return (Number(a) - Number(b));
//});
var str = '';
for (var j = 0; j < keys.length; j++) {
str += JSON.stringify(keys[j]);
str += JSON.stringify(arr[i][keys[j]]);
}
if (!obj.hasOwnProperty(str)) {
newArr.push(arr[i]);
obj[str] = true;
}
}
return newArr;
}
3. Ordinary array deduplication
function unipFunc(arr) {
let newArr = [];
for (var i = 0; i < arr.length; i++) {
if (newArr.indexOf(arr[i]) === -1) {
newArr.push(arr[i]);
}
}
return newArr;
}
4. Ordinary arrays get repeated elements
方法一：indexOf和lastIndexOf
function unipFunc(arr) {
let newArr = [];
arr.forEach((item)=>{
if(arr.indexOf(item) !== arr.lastIndexOf(item) && newArr.indexOf(item) === -1){
newArr.push(item);
}
});
return newArr;
}
方法二：双层for循环
function unipFunc(arr) {
var Arr = [];
for(let i=0; i<arr.length; i++ ){
for(let j=i+1; j<arr.length; j++){
if(arr[i]===arr[j] && Arr.indexOf(arr[j])===-1){
Arr.push(arr[i]);
}
}
}
return Arr;
}
5. Array nested objects, get repeated elements and unique elements and coordinates
//数据
const arr =[
{
id:1, schoolId:'100', jointCategoryName:'美术'},
{
id:2, schoolId:'200', jointCategoryName:'美术'},
{
id:3, schoolId:'300', jointCategoryName:'设计'},
{
id:4, schoolId:'100', jointCategoryName:'音乐'},
{
id:3, schoolId:'300', jointCategoryName:'设计'},
{
id:2, schoolId:'400', jointCategoryName:'美术'}
]
let key = {
} //存储的 key 是type的值，value是在indeces中对应数组的下标
let indices = [] //数组中每一个值是一个数组，数组中的每一个元素是原数组中相同type的下标
arr.map((item, index) => {
//根据对应字段 分类（type）
let type= item.type
let _index = key[type]
if (_index !== undefined) {
indices[_index].push(index)
} else {
key[type] = indices.length
indices.push([index])
}
})
// 归类结果
let result = []
indices.map((item) => {
item.map((index) => {
//result.push(List[index]) 相同项排序在一起
//if (item.length > 1) {} 只要重复项
//if (item.length == 1){} 只要单独项
//我这里需要重复项 根据业务处理
if (item.length > 1) {
result.push(arr[index])
}
})
})
console.log('获取重复的值=====================>',result[0].type)
return result;
6. Map()
let arrObj = [
{
id:1, schoolId:'100', jointCategoryName:'美术'},
{
id:2, schoolId:'200', jointCategoryName:'美术'},
{
id:3, schoolId:'300', jointCategoryName:'设计'},
{
id:4, schoolId:'100', jointCategoryName:'音乐'},
{
id:3, schoolId:'300', jointCategoryName:'设计'},
{
id:2, schoolId:'400', jointCategoryName:'美术'}
];
// 方法一：
let map = new Map();
for (let item of arrObj) {
if (!map.has(item.id)) {
map.set(item.id, item);
};
};
arr = [...map.values()];
console.log(arr);
// 方法二： (代码较为简洁)
const map = new Map();
const newArr = arrObj.filter(v => !map.has(v.id) && map.set(v.id, 1));
console.log(newArr);
7. Array deduplication
Normal array deduplication
let arr = [1, 1, 1, 2, 3, 4, 5, 5, 6];
let crr = [];
const res = arr.reduce((brr, va) => {
if (!brr.includes(va)) {
brr.push(va);
} else {
crr.push(va);
}
return brr;
}, []);
console.log(res);
console.log(crr);
Array Object Deduplication
Method 1
let arr = [{
label:'你好',prop:'aa'},{
label:'你好',prop:'aa'},{
label:'你好2',prop:'bb1'},{
label:'你好2',prop:'bb2'}]
let deWeightArr = []; // 去重后的数组
let repetitionArr = []; // 重复的数组
arr.forEach((item1) => {
const check = deWeightArr.every((item2) => {
return item1.prop !== item2.prop;
});
check ? deWeightArr.push(item1) : repetitionArr.push(item1);
});
console.log('重复的数据================>>>>>',repetitionArr)
console.log('获取数组去重后的数据================>>>>>',deWeightArr)
Method Two
this.repeatData = [];
dataList.forEach((item) => {
if (
this.repeatData.filter((material) => material.archiveRank === item.archiveRank)
.length === 0
) {
this.repeatData.push(item);
}
});
console.log('获取重复的数组数据=====》<<<<<<<<<<<<<<<<<<<<<<<',this.repeatData)
Native deduplication
let arr =
[
{
id:1, schoolId:'100', jointCategoryName:'美术'},
{
id:2, schoolId:'200', jointCategoryName:'美术'},
{
id:3, schoolId:'300', jointCategoryName:'设计'},
{
id:4, schoolId:'100', jointCategoryName:'音乐'},
{
id:3, schoolId:'300', jointCategoryName:'设计'},
{
id:2, schoolId:'400', jointCategoryName:'美术'}
];
export const distinct = (arr) => {
var result = [];
var obj = {
};
for (var i = 0; i < arr.length; i++) {
if (!obj[arr[i].jointCategoryName]) {
result.push(arr[i]);
obj[arr[i].jointCategoryName] = true;
}
}
console.log('获取重复的数组数据=====》<<<<<<<<<<<<<<<<<<<<<<<',result)
return result;
};
distinct(arr)