从给定的数组创建一个新数组并获得不同的属性作为子 object/Array

Question

我的 Responses 数组有多个 ID 但问题答案不同。

Responses = 
[0:{Id : 1,Name : John, QuestionId :1,Answer :8},
1:{Id : 1,Name : John, QuestionId :2,Answer :9},
2:{Id : 1,Name : John, QuestionId :3,Answer :3},
3:{Id : 1,Name : John, QuestionId :4,Answer :2},
4:{Id : 2,Name : Mark, QuestionId :1,Answer :6},
5:{Id : 2,Name : Mark, QuestionId :2,Answer :2},
6:{Id : 2,Name : Mark, QuestionId :3,Answer :5},
7:{Id : 2,Name : Mark, QuestionId :4,Answer :1}]
----------------------------------------------------------------
Output I want :
 
Arr = 
[0:{Id : 1,Name : John,
 Question : [{QuestionId :1,Answer :9},{QuestionId :2,Answer :8},{QuestionId :3,Answer :3},{QuestionId :4,Answer :2}]},
1:{Id : 2,Name : Mark,
 Question : [{QuestionId :1,Answer :6},{QuestionId :2,Answer :2},{QuestionId :3,Answer :5},{QuestionId :4,Answer :1}]}]
---------------------------------------------------------

我想创建一个包含 ID、名称和一个问题对象的数组，该对象将包含问题 ID 和答案。我尝试了不同的方式，但这对我不起作用。如果你能在这里帮助我，那就太好了。谢谢。

Answer 1

const a = [{Id : 1,Name : 'John', QuestionId :1,Answer :8},
           {Id : 1,Name : 'John', QuestionId :2,Answer :9},
           {Id : 1,Name : 'John', QuestionId :3,Answer :3},
           {Id : 1,Name : 'John', QuestionId :4,Answer :2},
           {Id : 2,Name : 'Mark', QuestionId :1,Answer :6},
           {Id : 2,Name : 'Mark', QuestionId :2,Answer :2},
           {Id : 2,Name : 'Mark', QuestionId :3,Answer :5},
           {Id : 2,Name : 'Mark', QuestionId :4,Answer :1}]

const result = a.reduce((acc,curVal,index,src)=>{
    const {Id, Name, QuestionId,Answer} = curVal
    if(index===0 ){
        acc.push({Id,Name,Question:[{QuestionId, Answer}]})
    }else{
        const itemId = acc.findIndex(el=>el.Id===curVal.Id)
        if(itemId>= 0){
            acc[itemId].Question.push({QuestionId, Answer})
        }else{
            acc.push({Id,Name,Question:[{QuestionId, Answer}]})
        }
    }
  
    return acc
},[])

console.log(result)

Answer 2

您首先必须按 Name 对数据进行分组。获得分组数据后，映射值。映射时，可以解构第一个问题的Id和Name字段，然后将QuestionId和Answer字段映射到Question字段。

const groupBy = (arr, key) => arr.reduce((acc, item) => ({
  ...acc,
  [item[key]]: [ ...(acc[[item[key]]] ?? []), item ]
}), {});

const responses = [
  { "Id": 1, "Name": "John", "QuestionId": 1, "Answer": 8 },
  { "Id": 1, "Name": "John", "QuestionId": 2, "Answer": 9 },
  { "Id": 1, "Name": "John", "QuestionId": 3, "Answer": 3 },
  { "Id": 1, "Name": "John", "QuestionId": 4, "Answer": 2 },
  { "Id": 2, "Name": "Mark", "QuestionId": 1, "Answer": 6 },
  { "Id": 2, "Name": "Mark", "QuestionId": 2, "Answer": 2 },
  { "Id": 2, "Name": "Mark", "QuestionId": 3, "Answer": 5 },
  { "Id": 2, "Name": "Mark", "QuestionId": 4, "Answer": 1 }
];

const arr = Object.values(groupBy(responses, 'Name')).map(questions => {
  const [ { Id, Name } ] = questions;
  return {
    Id, Name, Question: questions.map(({ QuestionId, Answer }) =>
      ({ QuestionId, Answer }))
  };
});

console.log(arr);

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或者，您可以跳过分组，只减少。这有点耦合，但它切断了映射。

const reduceBy = (arr, key) => Object.values(arr.reduce((acc, item) => {
  const
    { Id, Name, QuestionId, Answer } = item,
    prev = acc[[item[key]]] || { Id, Name, Question: [] };
  return {
    ...acc,
    [item[key]]: {
      ...prev,
      Question: [ ...prev.Question, { QuestionId, Answer } ]
    }
  };
}, {}));

const responses = [
  { "Id": 1, "Name": "John", "QuestionId": 1, "Answer": 8 },
  { "Id": 1, "Name": "John", "QuestionId": 2, "Answer": 9 },
  { "Id": 1, "Name": "John", "QuestionId": 3, "Answer": 3 },
  { "Id": 1, "Name": "John", "QuestionId": 4, "Answer": 2 },
  { "Id": 2, "Name": "Mark", "QuestionId": 1, "Answer": 6 },
  { "Id": 2, "Name": "Mark", "QuestionId": 2, "Answer": 2 },
  { "Id": 2, "Name": "Mark", "QuestionId": 3, "Answer": 5 },
  { "Id": 2, "Name": "Mark", "QuestionId": 4, "Answer": 1 }
];

const arr = reduceBy(responses, 'Name');

console.log(arr);

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Answer 3

const arr = [ 
  {Id : 1,Name : "John", QuestionId :1,Answer :8},
  {Id : 1,Name : "John", QuestionId :2,Answer :9},
  {Id : 1,Name : "John", QuestionId :3,Answer :3},
  {Id : 1,Name : "John", QuestionId :4,Answer :2},
  {Id : 2,Name : "Mark", QuestionId :1,Answer :6},
  {Id : 2,Name : "Mark", QuestionId :2,Answer :2},
  {Id : 2,Name : "Mark", QuestionId :3,Answer :5},
  {Id : 2,Name : "Mark", QuestionId :4,Answer :1}
]

let newObj = {};
arr.forEach(({ Id, Name, QuestionId, Answer }) => {
  if(newObj[Id]) {
    newObj[Id]["Question"] = [
      ...newObj[Id]["Question"],
      { QuestionId, Answer }
    ]
  } else {
    newObj[Id] = {
      Id,
      Name,
      Question: [{ QuestionId, Answer }]
    } 
  }
})

console.log(Object.values(newObj).flat());

Answer 4

您可以使用 Set 提取唯一名称，然后使用这些名称过滤 Resopnses 数组中的项目：

let Responses=[{Id:1,Name:"John",QuestionId:1,Answer:8},{Id:1,Name:"John",QuestionId:2,Answer:9},{Id:1,Name:"John",QuestionId:3,Answer:3},{Id:1,Name:"John",QuestionId:4,Answer:2},{Id:2,Name:"Mark",QuestionId:1,Answer:6},{Id:2,Name:"Mark",QuestionId:2,Answer:2},{Id:2,Name:"Mark",QuestionId:3,Answer:5},{Id:2,Name:"Mark",QuestionId:4,Answer:1}];

let result = [...new Set(Responses.map(({Name}) => Name))]
    .map(e => Responses.filter(({Name}) => Name === e))
    
console.log(result)

从给定的数组创建一个新数组并获得不同的属性作为子 object/Array

Create one new array from given array and get different properties as a Child object/Array

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