使用值将数组中对象的属性合并在一起并删除重复项

Posted 2023-02-22

【中文标题】使用值将数组中对象的属性合并在一起并删除重复项

【英文标题】：Merge properties of objects within a array together using values and remove duplicate

【发布时间】：2022-01-08 01:25:44

【问题描述】：

如果javascript中的值相同，我想知道如何将对象的属性与相同的对象数组合并。

我的输入数据

var input = [
       student: 'Alex', class: 'ten', subject: 'maths', marks: '85', answer: 'Moderate', percentage: '90', sports: 'good' ,
     student: 'Alex', class: 'ten', subject: 'maths', marks: '85', answer: 'Moderate', percentage: '90', sports: 'good' ,
     student: 'Alex', class: 'nine', subject: 'science', marks: '82', answer: 'Severe', percentage: '85', sports: 'good' ,
     student: 'Alex', class: 'nine', subject: 'science', marks: '82', answer: 'Severe', percentage: '85', sports: 'good' ,
     student: 'Alex', class: 'eight', subject: 'computer', marks: '90', answer: 'Extreme', percentage: '87', sports: 'good' ,
     student: 'Alex', class: 'eight', subject: 'computer', marks: '90', answer: 'Extreme', percentage: '87', sports: 'good' ,
     student: 'john', class: 'ten', subject: 'maths', marks: '90', answer: 'Extreme', percentage: '99', sports: 'good' ,
     student: 'john', class: 'ten', subject: 'maths', marks: '90', answer: 'Extreme', percentage: '99', sports: 'good' ,
     student: 'john', class: 'nine', subject: 'science', marks: '85', answer: 'Moderate', percentage: '100', sports: 'good' ,
     student: 'john', class: 'nine', subject: 'science', marks: '85', answer: 'Moderate', percentage: '100', sports: 'good' ,
     student: 'john', class: 'eight', subject: 'computer', marks: '87', answer: 'Extreme', percentage: '67', sports: 'good' ,
     student: 'john', class: 'eight', subject: 'computer', marks: '87', answer: 'Extreme', percentage: '67', sports: 'good' ,
]

预期输出：

[
    student: 'Alex',class: 'ten', maths: '85', science: '82',computer:'90', answer: 'Moderate', percentage: '90', sports: 'good',
     student: 'Alex',class: 'nine', maths: '85', science: '82',computer:'90', answer: 'Moderate', percentage: '85', sports: 'good',
     student: 'Alex',class: 'eight', maths: '85', science: '82',computer:'90', answer: 'Moderate', percentage: '87', sports: 'good',
     student: 'john',class: 'ten',maths: '90', science: '85',computer:'87',answer: 'Extreme', percentage: '99', sports: 'good',
     student: 'john',class: 'nine',maths: '90', science: '85',computer:'87',answer: 'Extreme', percentage: '100', sports: 'good',
     student: 'john',class: 'eight',maths: '90', science: '85',computer:'87',answer: 'Extreme', percentage: '67', sports: 'good',
]

我试过下面的代码

    const output = data.reduce((a, v) => 
    const key = i.student + i.subject;
    const subjectKey = v.subject
    if (a[key]) 
        a[key] = 
            ...v,
            [subjectKey]: v.marks,
        
     else 
        a[key] = v
    
    return a
, )
console.log(Object.values(output))

【问题讨论】：

您将丢失一些当前预期输出的数据（answers 对于每个对象都不同）。对象结构应该是name:'Alex', courses:[subject:'Math',marks: '90', answer: 'Extreme' , subject:'Science',marks:'90',answer: 'Moderate' ]... 学生名也可以相同，必须有一些标识符。

【参考方案1】：

var input=[student:"Alex",subject:"maths",marks:"85",answer:"Moderate",student:"Alex",subject:"maths",marks:"85",answer:"Moderate",student:"Alex",subject:"maths",marks:"85",answer:"Moderate",student:"Alex",subject:"science",marks:"82",answer:"Severe",student:"Alex",subject:"science",marks:"82",answer:"Severe",student:"Alex",subject:"science",marks:"82",answer:"Severe",student:"Alex",subject:"computer",marks:"90",answer:"Extreme",student:"Alex",subject:"computer",marks:"90",answer:"Extreme",student:"Alex",subject:"computer",marks:"90",answer:"Extreme",student:"john",subject:"maths",marks:"90",answer:"Extreme",student:"john",subject:"maths",marks:"90",answer:"Extreme",student:"john",subject:"maths",marks:"90",answer:"Extreme",student:"john",subject:"science",marks:"85",answer:"Moderate",student:"john",subject:"science",marks:"85",answer:"Moderate",student:"john",subject:"science",marks:"85",answer:"Moderate",student:"john",subject:"computer",marks:"87",answer:"Extreme",student:"john",subject:"computer",marks:"87",answer:"Extreme",student:"john",subject:"computer",marks:"87",answer:"Extreme"];

//find all unique inputs, i.e. entry with unique strudent and subject
var uniqueInput = [...input].reduce((unique, obj) => 
  if (unique.filter((student,subject) => student === obj.student && subject === obj.subject /* && otherKeyFeatureUsedForUniqueness */).length === 0) return [...unique, obj]; //if not already inserted
    return unique; //already inserted
, [])

var finalArray = [...uniqueInput].reduce((alreadyInsertedStudent, currentStudent) => 
    //get array of students without current student
    var arrWithoutObj = alreadyInsertedStudent.filter((student) => student !== currentStudent.student /* && the student or class or other properties which is constant across the duplicated rows in original input array, you can add here*/); 
    
    //if the student is not present, then withoutArray === currentarray
    //if yes, then insert the student and subject 
  if (arrWithoutObj.length === alreadyInsertedStudent.length) return [...alreadyInsertedStudent, student: currentStudent.student, [currentStudent.subject]: currentStudent.marks, answer: currentStudent.answer/*, ...rest additional unique row defining Properties of final answer, you can add here*/];
    //if student already inserted, then add the subject marks to that student 
    return [...alreadyInsertedStudent].map((prev) => prev.student === currentStudent.student ? ...prev, [currentStudent.subject]:currentStudent.marks : prev);
, [])

console.log(finalArray)

【讨论】：

看起来不错，himanshu，需要多加一个字段即answera

如果输入数据对象有更多的键值对我应该怎么做例如`学生：'Alex'，主题：'数学'，标记：'85'，答案：'中等',loe:'xyz',cmets:'干得好', `

为此用例编辑了帖子

我用新的数据集更新了帖子

这个解决方案是一个示例，您可以借助 cmets 理解它。根据新数据进行更新将很容易。你可以试试看。你可以再查看一下cmets，我已经更新了。