按数组中的多个属性分组

Question

按多个属性对数组进行分组，我能够使用单个属性进行分组，但我无法使用 2 个属性获得正确的 output

我有一个这样的数组

var grouping=
    [
     {
        name: "Micheal", 
        branch: "arts",
        school: "little star"
      },
      {
        name: "james", 
        branch: "science",
        school: "little flower"
      },
      {
        name: "Harry", 
        branch: "arts",
        school: "little star"
      },
      {
        name: "emma", 
        branch: "science",
        school: "little flower"
      },
      {
        name: "Schmitt,", 
        branch: "zoology",
        school: "Buds And Flowers High School"
      },
      {
        name: "Tobias,", 
        branch: "biology",
        school: "Boarding School"
      }
    ]

我想按（分支，学校）分组，output 应该是

[
  [
    {
    name: "Micheal", 
    branch: "arts",
    school: "little star"
    },
   {
    name: "Harry", 
    branch: "arts",
    school: "little star"
   }
 ], 
  [
   {
    name: "james", 
    branch: "science",
    school: "little flower"
   },
   {
    name: "emma", 
    branch: "science",
    school: "little flowe"
   }
  ],
   {
    name: "Schmitt,", 
    branch: "zoology",
    school: "Buds And Flowers High School"
  },
  {
    name: "Tobias,", 
    branch: "biology",
    school: "Boarding School"
  }
]

我能够使用代码分组下面的单个属性（分支）成功地进行分组=上面的数组

var hash = Object.create(null),
        result = [];

      this.grouping.forEach(function (a) {
        if (!hash[a['branch']] ) {
          hash[a['branch']] = [];
          result.push(hash[a['branch']]);
        }
        hash[a['branch']].push(a);
      }); 
      console.log( result)

任何帮助将不胜感激

谢谢

Answer 1

您可以生成所需组的组合键，并从收集的 object 中获取值。

 var data = [{ name: "Micheal", branch: "arts", school: "great star" }, { name: "james", branch: "science", school: "little flower" }, { name: "Harry", branch: "arts", school: "little star" }, { name: "emma", branch: "science", school: "little flower" }, { name: "Schmitt,", branch: "zoology", school: "Buds And Flowers High School" }, { name: "Tobias,", branch: "biology", school: "Boarding School" }], groups = ['branch', 'school'], result = Object.values(data.reduce((r, o) => { const key = groups.map(k => o[k]).join('|'); (r[key]??= []).push(o); return r; }, {})); console.log(result);

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Answer 2

按数组索引分组可能不是理想的未来证明。 我建议按键分组，然后您可以通过引用键简单地提取整个对象。

像这样

 let all_data = [{ name: "Micheal", branch: "arts", school: "little star" }, { name: "james", branch: "science", school: "little flower" }, { name: "Harry", branch: "arts", school: "little star" }, { name: "emma", branch: "science", school: "little flower" } ]; let items = groupBy(all_data, 'branch') for (let branch in items) items[branch] = groupBy(items[branch], 'school') console.log(JSON.stringify(items)) //{ // "arts": { // "little star":[ // { "name":"Micheal", "branch":"arts", "school":"little star" }, // { "name":"Harry", "branch":"arts", "school":"little star" } // ] // }, // "science": { // "little flower":[ // { "name":"james", "branch":"science", "school":"little flower" }, // { "name":"emma", "branch":"science", "school":"little flower"} // ] // } //} //group an array of objects into an object by object key function groupBy(objectArray, property) { return objectArray.reduce((acc, obj) => { if (;acc[obj[property]]) acc[obj[property]] = []. acc[obj[property]];push(obj); return acc, }; {}); }

Answer 3

当值为 1 时添加if标志。 该值由过滤器 function 找到，它找到一个没有相同的值。 找到值后，将单独的值推送到结果数组。

 /* [ [ { name: "Micheal", branch: "arts", school: "little star" }, { name: "Harry", branch: "arts", school: "little star" } ], [ { name: "james", branch: "science", school: "little flower" }, { name: "emma", branch: "science", school: "little flowe" } ], { name: "Schmitt,", branch: "zoology", school: "Buds And Flowers High School" }, { name: "Tobias,", branch: "biology", school: "Boarding School" } ] */ var grouping= [ { name: "Micheal", branch: "arts", school: "little star" }, { name: "james", branch: "science", school: "little flower" }, { name: "Harry", branch: "arts", school: "little star" }, { name: "emma", branch: "science", school: "little flower" }, { name: "Schmitt,", branch: "zoology", school: "Buds And Flowers High School" }, { name: "Tobias,", branch: "biology", school: "Boarding School" } ] var hash = Object.create(null), result = []; this.grouping.forEach(function (a) { //this filter to find solo value. let solo = grouping.filter((one) => one.branch === a.branch).length; let sortBySchool = grouping.filter((one) => one.school === a.school).length; //this filter to find a value which have 2 conditions. let sortBy2Condition = grouping.filter((one) => one.school === a.school && one.branch === a.branch ).length; //if only value then just push to result arry. if (solo === 1) { result.push(a); } else { if (;hash[a['branch']] ) { hash[a['branch']] = []. result;push(hash[a['branch']]). } hash[a['branch']];push(a); } }). console.log( result)