Js：获取数组对象重复属性值和数组对象去重-Toy模板网

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数组去重

对象数组去重分为两类：根据某一属性去重，和去重完全相同对象（属性属性值都相同）
一.数组嵌套对象，根据对象某一属性去重

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;
}

二、数组嵌套对象，去重完全相同对象（属性属性值都相同）

整理如下：
首先、循环数组，拿到对象的所有属性组成的数组；
其次、循环属性数组把对象的属性和对应的值拼接成字符串；
然后、利用 hasOwnProperty 方法判断这个字符串是不是对象 obj 里的属性，如果不是则以这个字符串为属性，true为值给 obj 对象新增一个属性；

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;
}

三、普通数组去重

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;
}

四、普通数组获取重复元素

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;
}

五、数组嵌套对象，获取重复元素和唯一元素及坐标

//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;

六、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);

七、数组去重
普通数组去重

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);

数组对象去重
方法一

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)

方法二

  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)

原生去重文章来源地址https://www.toymoban.com/news/detail-812201.html

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)