如何比较两个对象并在javascript中按值删除重复的对象答案

【问题标题】：How to compare two objects and remove the duplicate objects by value in javascript如何比较两个对象并在javascript中按值删除重复的对象
【发布时间】：2018-10-29 07:39:35
【问题描述】：

我有两个对象，我想比较这些对象并按值删除重复的对象并显示其余对象。我尝试了 lodash omit 但它不起作用。

    let users = [
  {value: "6qcuXSLWAnVospWkugWa", label: "Karthi"},
  {value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"},
  {value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"},
  {value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"},
  {value: "km2jHXDQgPXdBY4jq6dG", label: "User50"},
  {value: "ObQhbfH3YroudLVz5YkY", label: "User10"}
]

let selectedUsers = [
{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"},
{value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"},
{value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"},
{value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"},
{value: "km2jHXDQgPXdBY4jq6dG", label: "User50"},
{value: "ObQhbfH3YroudLVz5YkY", label: "User10"},
{value: "L9FW5oXDlDmzhWxhGEdu", label: "Govind"}
]

不使用多个循环是否可以删除重复项

【问题讨论】：

为什么users和selectedUsers是对象而不是数组？
预期输出是什么？
@David 这是一个错字它只是数组
Compare two Javascript Arrays and remove Duplicates的可能重复
How to determine equality for two JavaScript objects?的可能重复

标签： javascript reactjs lodash

【解决方案1】：

var userObjectOfObjects = users.reduce(
        (acc, o) => {
            acc[o.value] = o;
            return acc;
        }, {} )

var selectUsersObject = selectedUsers.reduce(
    (acc, o) => {
        if(userObjectOfObjects[o.value]){
            acc.duplicates.push(o)
            return acc;
        }
        else {
            acc.objectWithoutDuplicates.push(o)
        }
        acc.uniqueList[o.value] = o;
        return acc;
    }, { uniqueList: {}, objectWithoutDuplicates:[], duplicates: [] } )


selectUsersObject.uniqueList = {
    ...selectUsersObject.uniqueList,
    ...userObjectOfObjects
}

var uniqueList = Object.values(selectUsersObject.uniqueList)
var duplicates = selectUsersObject.duplicates
var noRepetition = selectUsersObject.objectWithoutDuplicates

【讨论】：

【解决方案2】：

let result = _.unionBy(users, selectedUsers, 'value');

【讨论】：

@MatthieuBrucher 它本质上是按值返回唯一对象。
@MatthieuBrucher 我认为这是不言自明的。

【解决方案3】：

您可以使用differenceWith 和isEqual 从selectedUsers 中获取唯一值。

let users = [{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"}, {value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"}, {value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"}, {value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"}, {value: "km2jHXDQgPXdBY4jq6dG", label:
"User50"}, {value: "ObQhbfH3YroudLVz5YkY", label: "User10"}],
    selectedUsers = [{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"}, {value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"}, {value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"}, {value: "WE6kIW8sGkEuMRXQgQPT",
label: "User8"}, {value: "km2jHXDQgPXdBY4jq6dG", label: "User50"}, {value: "ObQhbfH3YroudLVz5YkY", label: "User10"}, {value: "L9FW5oXDlDmzhWxhGEdu", label: "Govind"}],
    result = _.differenceWith(selectedUsers, users, _.isEqual);
console.log(result);

&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"&gt;&lt;/script&gt;

【讨论】：

【解决方案4】：

假设要复制的对象，value 和 label 的值应该相同。

您可以尝试使用具有线性复杂度的简单 Javascript 进行跟踪。首先将users数组转换成一个对象，然后在第二个数组上使用Array.filter，过滤掉重复的对象。

let users = [{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"},{value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"},{value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"},{value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"},{value: "km2jHXDQgPXdBY4jq6dG", label: "User50"},{value: "ObQhbfH3YroudLVz5YkY", label: "User10"}];
let selectedUsers = [{value: "6qcuXSLWAnVospWkugWa", label: "Karthi"},{value: "Qk8pc08WmcacM7BqFxow", label: "Karthi"},{value: "evLkHAkhNZ9qqeYc1tDn", label: "Sankar"},{value: "WE6kIW8sGkEuMRXQgQPT", label: "User8"},{value: "km2jHXDQgPXdBY4jq6dG", label: "User50"},{value: "ObQhbfH3YroudLVz5YkY", label: "User10"},{value: "L9FW5oXDlDmzhWxhGEdu", label: "Govind"}];

let uersObj = users.reduce((a,c) => Object.assign(a, {[c.value]:c.label}), {});
let result = selectedUsers.filter(v => !uersObj[v.value] || uersObj[v.value] !== v.label);
console.log(result);

【讨论】：

【解决方案5】：

对此的任何解决方案都需要多个循环。要么你写了多个循环，要么你写的速记代码在内部使用了多个循环。

这个单线应该适合你

const arrWithoutDup = selectedUsers.filter(sUser => users.filter(user => sUser.value === user.value && sUser.value === user.value).length === 0);

【讨论】：