按對象按數組對象分組

Question

我有一個這樣的對象數組：

[{ name: 'Peter', age: '22',  hobby: 'soccer', city: 'london' }, 
 { name: 'Mario', age: '30',  hobby: 'bike', city: 'Paris' }, 
 { name: 'Peter', age: '22',  hobby: 'soccer', city: 'Paris' }, 
 { name: 'Mario', age: '30',  hobby: 'bike', city: 'Madrid' }, 
 { name: 'Rick', age: '28',  hobby: 'tennis', city: 'Berlin' }],

我想按城市分組，如下所示：

[{name: 'Peter', age: '22',  hobby: 'soccer', cities: ['london', 'Paris']},
 {name: 'Mario', age: '30',  hobby: 'bike',cities: ['Paris', 'Madrid']}, 
 {name: 'Rick', age: '28',  hobby: 'tennis', cities: ['Berlin']}]

我嘗試使用這個函數，我沒有好的數組

let arrayPeople = [{ name: 'Peter', age: '22',  hobby: 'soccer', city: 'london' }, 
 { name: 'Mario', age: '30',  hobby: 'bike', city: 'Paris' }, 
 { name: 'Peter', age: '22',  hobby: 'soccer', city: 'Paris' }, 
 { name: 'Mario', age: '30',  hobby: 'bike', city: 'Madrid' }, 
 { name: 'Rick', age: '28',  hobby: 'tennis', city: 'Berlin' }],

 let groups = {};
 for (let i = 0; i < arrayPeople.length; i++) {
   let groupName = arrayPeople[i].city;
   if (!groups[groupName]) {
    groups[groupName] = [];
   }
   groups[groupName].push(arrayPeople[i].city);
 }
 let arrayGroupBy= [];
 for (let groupName in groups) {
   arrayGroupBy.push({ ...arrayPeople, cities: groups[groupName] });
 }

我怎樣才能讓我的小組通過？

感謝您的幫助。

Answer 1

您的方法非常接近正確的解決方案。 您正在按城市對人員進行分組。 你必須轉身，按人分組城市

let arrayPeople = [{ name: 'Peter', age: '22',  hobby: 'soccer', city: 'london' }, 
 { name: 'Mario', age: '30',  hobby: 'bike', city: 'Paris' }, 
 { name: 'Peter', age: '22',  hobby: 'soccer', city: 'Paris' }, 
 { name: 'Mario', age: '30',  hobby: 'bike', city: 'Madrid' }, 
 { name: 'Rick', age: '28',  hobby: 'tennis', city: 'Berlin' }];

let groups = {};
for (let i = 0; i < arrayPeople.length; i++) {
  let groupName = arrayPeople[i].name;
  if (!groups[groupName]) {
   groups[groupName] = {name: arrayPeople[i].name, age: arrayPeople[i].age, hobby: arrayPeople[i].hobby, cities: []};
  }
  groups[groupName].cities.push(arrayPeople[i].city);
}
 
console.log(Object.values(groups));

Answer 2

這是 TypeScript，所以我可能會想出與最終數組元素相對應的類型：也就是說，刪除city屬性並添加一個cities屬性：

type PersonCities = Omit<typeof arrayPeople[number], "city"> & { cities: string[] };

然后，您想將所有對象放入以您希望分組條件為鍵的字典中（轉換為字符串）：

const peopleCities: Record<string, PersonCities> = {};
for (let p of arrayPeople) {
  const { city, ...person } = p;
  const groupByKey = JSON.stringify([person.name, person.hobby, person.age]);
  if (!(groupByKey in peopleCities)) {
    peopleCities[groupByKey] = { ...person, cities: [] };
  }
  peopleCities[groupByKey].cities.push(city);
}
const arrayPeopleCities = Object.values(peopleCities);

在這里，我們將分組鍵設為數組中name 、 hobby和age屬性的 JSON 字符串。 和一些對象休息/傳播語法來復制人們的屬性而沒有太多冗余。

Playground 鏈接到代碼

Answer 3

您可以使用Array.reduce處理您的輸入數組，使用名稱、年齡和愛好作為鍵來創建分組對象，並將每個鍵的城市添加到該對象中的數組中。 然后，您可以使用Object.values將分組對象中的值抓取到數組中：

 let arrayPeople = [{ name: 'Peter', age: '22', hobby: 'soccer', city: 'london' }, { name: 'Mario', age: '30', hobby: 'bike', city: 'Paris' }, { name: 'Peter', age: '22', hobby: 'soccer', city: 'Paris' }, { name: 'Mario', age: '30', hobby: 'bike', city: 'Madrid' }, { name: 'Rick', age: '28', hobby: 'tennis', city: 'Berlin' }]; let arrayGroupBy = Object.values(arrayPeople.reduce((c, { city, ...rest }) => { let key = Object.values(rest).join('#'); c[key] = c[key] || { ...rest, city : [] }; c[key].city.push(city); return c; }, {})); console.log(arrayGroupBy);

請注意，上面的代碼取決於對象中的屬性在每個對象中的順序相同（在示例數據中， name ， age ， hobby ）。 如果情況並非如此，您將需要使用命名屬性創建密鑰，例如：

 let arrayPeople = [{ name: 'Peter', age: '22', hobby: 'soccer', city: 'london' }, { age: '30', hobby: 'bike', name: 'Mario', city: 'Paris' }, { name: 'Peter', hobby: 'soccer', city: 'Paris', age: '22' }, { name: 'Mario', age: '30', hobby: 'bike', city: 'Madrid' }, { name: 'Rick', age: '28', hobby: 'tennis', city: 'Berlin' }]; let arrayGroupBy = Object.values(arrayPeople.reduce((c, { name, age, hobby, city}) => { let key = `${name}#${age}#${hobby}`; c[key] = c[key] || { name, age, hobby, city : [] }; c[key].city.push(city); return c; }, {})); console.log(arrayGroupBy);

另請注意，以上所有代碼都取決於選擇不會出現在name或hobby值中的分隔符（我使用過# ）。 如果沒有合適的分隔符，那么使用JSON.stringify類的JSON.stringify來生成key會更安全，例如您將使用的第二個代碼塊：

let key = JSON.stringify([name, age, hobby]);