按数组中的多个属性对对象进行分组，然后汇总它们的值

Question

Grouping elements in array by multiple properties是与我的问题最接近的匹配，因为它确实通过数组中的多个键对对象进行分组。问题是这个解决方案没有总结属性值然后删除重复项，而是将所有重复项嵌入到二维数组中。

预期行为

我有一组对象，必须按shape和color分组。

var arr = [
    {shape: 'square', color: 'red', used: 1, instances: 1},
    {shape: 'square', color: 'red', used: 2, instances: 1},
    {shape: 'circle', color: 'blue', used: 0, instances: 0},
    {shape: 'square', color: 'blue', used: 4, instances: 4},
    {shape: 'circle', color: 'red', used: 1, instances: 1},
    {shape: 'circle', color: 'red', used: 1, instances: 0},
    {shape: 'square', color: 'blue', used: 4, instances: 5},
    {shape: 'square', color: 'red', used: 2, instances: 1}
];

只有当shape和color相同时，此数组中的对象才会被视为重复项。如果是，我想分别总结他们的used和instances值，然后删除重复项。

因此，在此示例中，结果数组可能只包含四种组合：square red，square blue，circle red，circle blue

问题

我在这里尝试了一种更简单的方法：

var arr = [
    {shape: 'square', color: 'red', used: 1, instances: 1},
    {shape: 'square', color: 'red', used: 2, instances: 1},
    {shape: 'circle', color: 'blue', used: 0, instances: 0},
    {shape: 'square', color: 'blue', used: 4, instances: 4},
    {shape: 'circle', color: 'red', used: 1, instances: 1},
    {shape: 'circle', color: 'red', used: 1, instances: 0},
    {shape: 'square', color: 'red', used: 4, instances: 4},
    {shape: 'square', color: 'red', used: 2, instances: 2}
];

result = [];

arr.forEach(function (a) {
    if ( !this[a.color] && !this[a.shape] ) {
        this[a.color] = { color: a.color, shape: a.shape, used: 0, instances: 0 };
        result.push(this[a.color]);
    } 
    this[a.color].used += a.used;
    this[a.color].instances += a.instances;
}, Object.create(null));

console.log(result);

但输出

[{shape: "square", color: "red", used: 11, instances: 9},
{shape: "circle", color: "blue", used: 4, instances: 4}]

而非预期结果：

[{shape: "square", color: "red", used: 5, instances: 3},
{shape: "circle", color: "red", used: 2, instances: 1},
{shape: "square", color: "blue", used: 11, instances: 9},
{shape: "circle", color: "blue", used: 0, instances: 0}]

如何让我的功能按形状和颜色正确分组对象？即总结他们的价值并删除重复项？

Answer 1

将Array#reduce与辅助对象一起使用以对类似对象进行分组。对于每个对象，检查帮助程序中是否存在组合shape和color。如果没有，请使用Object#assign添加到帮助程序以创建对象的副本，然后推送到该数组。如果是，请将其值添加到used和instances。

var arr = [{"shape":"square","color":"red","used":1,"instances":1},{"shape":"square","color":"red","used":2,"instances":1},{"shape":"circle","color":"blue","used":0,"instances":0},{"shape":"square","color":"blue","used":4,"instances":4},{"shape":"circle","color":"red","used":1,"instances":1},{"shape":"circle","color":"red","used":1,"instances":0},{"shape":"square","color":"blue","used":4,"instances":5},{"shape":"square","color":"red","used":2,"instances":1}];

var helper = {};
var result = arr.reduce(function(r, o) {
  var key = o.shape + '-' + o.color;
  
  if(!helper[key]) {
    helper[key] = Object.assign({}, o); // create a copy of o
    r.push(helper[key]);
  } else {
    helper[key].used += o.used;
    helper[key].instances += o.instances;
  }

  return r;
}, []);

console.log(result);

如果您可以使用ES6，则使用Map收集值，然后通过spreading Map#values将其转换回数组：

const arr = [{"shape":"square","color":"red","used":1,"instances":1},{"shape":"square","color":"red","used":2,"instances":1},{"shape":"circle","color":"blue","used":0,"instances":0},{"shape":"square","color":"blue","used":4,"instances":4},{"shape":"circle","color":"red","used":1,"instances":1},{"shape":"circle","color":"red","used":1,"instances":0},{"shape":"square","color":"blue","used":4,"instances":5},{"shape":"square","color":"red","used":2,"instances":1}];

const result = [...arr.reduce((r, o) => {
  const key = o.shape + '-' + o.color;
  
  const item = r.get(key) || Object.assign({}, o, {
    used: 0,
    instances: 0
  });
  
  item.used += o.used;
  item.instances += o.instances;

  return r.set(key, item);
}, new Map).values()];

console.log(result);

Answer 2

您可以使用reduce()创建一个唯一shape|color属性对象和Object.values()来返回这些值的数组。

＆＃13;

＆＃13;

var arr =[{"shape":"square","color":"red","used":1,"instances":1},{"shape":"square","color":"red","used":2,"instances":1},{"shape":"circle","color":"blue","used":0,"instances":0},{"shape":"square","color":"blue","used":4,"instances":4},{"shape":"circle","color":"red","used":1,"instances":1},{"shape":"circle","color":"red","used":1,"instances":0},{"shape":"square","color":"blue","used":4,"instances":5},{"shape":"square","color":"red","used":2,"instances":1}]

var result = Object.values(arr.reduce(function(r, e) {
  var key = e.shape + '|' + e.color;
  if (!r[key]) r[key] = e;
  else {
    r[key].used += e.used;
    r[key].instances += e.instances
  }
  return r;
}, {}))

console.log(result)

＆＃13;

＆＃13;

＆＃13;

Answer 3

您可以使用哈希表和键来分组相同的组。

＆＃13;

＆＃13;

var array = [{ shape: 'square', color: 'red', used: 1, instances: 1 }, { shape: 'square', color: 'red', used: 2, instances: 1 }, { shape: 'circle', color: 'blue', used: 0, instances: 0 }, { shape: 'square', color: 'blue', used: 4, instances: 4 }, { shape: 'circle', color: 'red', used: 1, instances: 1 }, { shape: 'circle', color: 'red', used: 1, instances: 0 }, { shape: 'square', color: 'blue', used: 4, instances: 5 }, { shape: 'square', color: 'red', used: 2, instances: 1 }],
    hash = Object.create(null),
    grouped = [];
    
array.forEach(function (o) {
    var key = ['shape', 'color'].map(function (k) { return o[k]; }).join('|');
    
    if (!hash[key]) {
        hash[key] = { shape: o.shape, color: o.color, used: 0, instances: 0 };
        grouped.push(hash[key]);
    }
    ['used', 'instances'].forEach(function (k) { hash[key][k] += o[k]; });
});

console.log(grouped);

＆＃13;

.as-console-wrapper { max-height: 100% !important; top: 0; }

＆＃13;

＆＃13;

＆＃13;

Answer 4

  

使用此方法来指定多个属性：

 public static groupBy(array, f) {
       let groups = {};
       array.forEach(function (o) {
         var group = JSON.stringify(f(o));
         groups[group] = groups[group] || [];
         groups[group].push(o);
       });
    return Object.keys(groups).map(function (group) {
      return groups[group];
    })
 }

  

像这样调用此方法

var result = Utils.groupBy(arr, function (item) {
            return [item.shape, item.color];
          });

Answer 5

如果您需要基于color或shape属性的“二手”和“实例”数组；那么您可以使用此代码。

（PS：我知道这不是您想要的，但将来可能会帮助某人。为此，也正在重复使用Nenand's代码。如果该代码对您有用，请感谢他））

var array = [{ shape: 'square', color: 'red', used: 1, instances: 1 }, { shape: 'square', color: 'red', used: 2, instances: 1 }, { shape: 'circle', color: 'blue', used: 0, instances: 0 }, { shape: 'square', color: 'blue', used: 4, instances: 4 }, { shape: 'circle', color: 'red', used: 1, instances: 1 }, { shape: 'circle', color: 'red', used: 1, instances: 0 }, { shape: 'square', color: 'blue', used: 4, instances: 5 }, { shape: 'square', color: 'red', used: 2, instances: 1 }],


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

array.forEach(function (o) {
var key = ['shape', 'color'].map(function (k) { return o[k]; }).join('|');

if (!hash[key]) {
hash[key] = { shape: o.shape, color: o.color, YourArrayName : [] };
grouped.push(hash[key]);
}
['used'].forEach(function (k) { hash[key]['YourArrayName'].push({ used : o['used'], instances : o['instances'] }) });
});

console.log(grouped);

输出将像

Answer 6

我有一个建议给你。 如果您想让它更容易，您可以尝试使用Underscore库：http://underscorejs.org/

我尽快使用它并得到了正确的结果：

var arr = [
    {shape: 'square', color: 'red', used: 1, instances: 1},
    {shape: 'square', color: 'red', used: 2, instances: 1},
    {shape: 'circle', color: 'blue', used: 0, instances: 0},
    {shape: 'square', color: 'blue', used: 4, instances: 4},
    {shape: 'circle', color: 'red', used: 1, instances: 1},
    {shape: 'circle', color: 'red', used: 1, instances: 0},
    {shape: 'square', color: 'blue', used: 4, instances: 5},
    {shape: 'square', color: 'red', used: 2, instances: 1}
];

var byshape = _.groupBy(arr, 'shape');


var bycolor = _.map(byshape, function(array) {
                                    return _.groupBy(array, 'color')
                                });


var output = [];
_.each(bycolor, function(arrayOfShape) {
    _.each(arrayOfShape, function(arrayOfColor) {
    var computedItem = {shape: "", color: "", used: 0, instances: 0};
    _.each(arrayOfColor, function(item) {
        computedItem.shape = item.shape;
      computedItem.color = item.color;
        computedItem.used += item.used;
      computedItem.instances += item.instances;
    });
    output.push(computedItem);
  });
});
console.log(output);

http://jsfiddle.net/oLyzdoo7/

此解决方案将第一个数据分组，然后您可以执行您想要的操作，例如，计算数据为ypur wish。

也许您可以优化它，如果您需要更多帮助，请告诉我

Answer 7

/**
  * Groups an array of objects with multiple properties.
  *
  * @param  {Array}  array: the array of objects to group
  * @param  {Array} props: the properties to groupby
  * @return {Array} an array of arrays with the grouped results
  */   
const groupBy = ({ Group: array, By: props }) => {
    getGroupedItems = (item) => {
        returnArray = [];
        let i;
        for (i = 0; i < props.length; i++) {
            returnArray.push(item[props[i]]);
        }
        return returnArray;
    };

    let groups = {};
    let i;

    for (i = 0; i < array.length; i++) {
        const arrayRecord = array[i];
        const group = JSON.stringify(getGroupedItems(arrayRecord));
        groups[group] = groups[group] || [];
        groups[group].push(arrayRecord);
    }
    return Object.keys(groups).map((group) => {
        return groups[group];
    });
};

示例：

假设我们有一个对象数组。每个对象都包含有关一个人和所拥有金钱的信息。我们要为所有具有相同国籍和性别的人总结金钱。

const data = [
{Name: 'George', Surname: 'Best', Country: 'Great Britain', Gender: 'Male', Money:8000}, 
{Name: 'Orion', Surname: 'Papathanasiou', Country: 'Greece', Gender: 'Male', Money: 2000}, 
{Name: 'Mairy', Surname: 'Wellbeck', Country: 'Great Britain', Gender: 'Female', Money:5000}, 
{Name: 'Thanasis', Surname: 'Papathanasiou', Country: 'Greece',Gender: 'Male', Money: 3200},
{Name: 'George', Surname: 'Washington', Country: 'Great Britain', Gender: 'Male',Money:4200}, 
{Name: 'Orfeas', Surname: 'Kalaitzis', Country: 'Greece', Gender: 'Male', Money: 7643}, 
{Name: 'Nick', Surname: 'Wellington', Country: 'USA', Gender: 'Male', Money:1000}, 
{Name: 'Kostas', Surname: 'Antoniou', Country: 'Greece', Gender: 'Male', Money: 8712},
{Name: 'John', Surname: 'Oneal', Country: 'USA', Gender: 'Male', Money:98234}, 
{Name: 'Paulos', Surname: 'Stamou', Country: 'Greece',  Gender: 'Male', Money: 3422}, 
{Name: 'Soula', Surname: 'Spuropoulou', Country: 'Greece', Gender: 'Female', Money:400}, 
{Name: 'Paul', Surname: 'Pierce', Country: 'USA',  Gender: 'Male',Money: 13000},
{Name: 'Helen', Surname: 'Smith', Country: 'Great Britain', Gender: 'Female', Money:1000}, 
{Name: 'Cathrine', Surname: 'Bryant', Country: 'Great Britain', Gender: 'Female', Money: 8712},
{Name: 'Jenny', Surname: 'Scalabrini', Country: 'USA', Gender: 'Female', Money:92214}];

const groupByProperties = ['Country', 'Gender'];

调用函数：

const groupResult =  groupBy( {Group: data, By: groupByProperties} );

分组结果为：

  (6) [Array(2), Array(5), Array(3), Array(3), Array(1), Array(1)]
0: Array(2)
0: {Name: "George", Surname: "Best", Country: "Great Britain", Gender: "Male", Money: 8000}
1: {Name: "George", Surname: "Washington", Country: "Great Britain", Gender: "Male", Money: 4200}
length: 2
__proto__: Array(0)
1: Array(5)
0: {Name: "Orion", Surname: "Papathanasiou", Country: "Greece", Gender: "Male", Money: 2000}
1: {Name: "Thanasis", Surname: "Papathanasiou", Country: "Greece", Gender: "Male", Money: 3200}
2: {Name: "Orfeas", Surname: "Kalaitzis", Country: "Greece", Gender: "Male", Money: 7643}
3: {Name: "Kostas", Surname: "Antoniou", Country: "Greece", Gender: "Male", Money: 8712}
4: {Name: "Paulos", Surname: "Stamou", Country: "Greece", Gender: "Male", Money: 3422}
length: 5
__proto__: Array(0)
2: Array(3)
0: {Name: "Mairy", Surname: "Wellbeck", Country: "Great Britain", Gender: "Female", Money: 5000}
1: {Name: "Helen", Surname: "Smith", Country: "Great Britain", Gender: "Female", Money: 1000}
2: {Name: "Cathrine", Surname: "Bryant", Country: "Great Britain", Gender: "Female", Money: 8712}
length: 3
__proto__: Array(0)
3: Array(3)
0: {Name: "Nick", Surname: "Wellington", Country: "USA", Gender: "Male", Money: 1000}
1: {Name: "John", Surname: "Oneal", Country: "USA", Gender: "Male", Money: 98234}
2: {Name: "Paul", Surname: "Pierce", Country: "USA", Gender: "Male", Money: 13000}
length: 3
__proto__: Array(0)
4: Array(1)
0: {Name: "Soula", Surname: "Spuropoulou", Country: "Greece", Gender: "Female", Money: 400}
length: 1
__proto__: Array(0)
5: Array(1)
0: {Name: "Jenny", Surname: "Scalabrini", Country: "USA", Gender: "Female", Money: 92214}
length: 1
__proto__: Array(0)
length: 6
__proto__: Array(0)

因此，我们得到了6个数组。每个数组都按Country和Gender

分组

遍历每个数组，我们可以总结一下钱！

const groupBy = ({ Group: array, By: props }) => {
    getGroupedItems = (item) => {
        returnArray = [];
        let i;
        for (i = 0; i < props.length; i++) {
            returnArray.push(item[props[i]]);
        }
        return returnArray;
    };

    let groups = {};
    let i;

    for (i = 0; i < array.length; i++) {
        const arrayRecord = array[i];
        const group = JSON.stringify(getGroupedItems(arrayRecord));
        groups[group] = groups[group] || [];
        groups[group].push(arrayRecord);
    }
    return Object.keys(groups).map((group) => {
        return groups[group];
    });
};
	
	
const data = [
	{Name: 'George', Surname: 'Best', Country: 'Great Britain', Gender: 'Male', Money:8000}, 
	{Name: 'Orion', Surname: 'Papathanasiou', Country: 'Greece', Gender: 'Male', Money: 2000}, 
    {Name: 'Mairy', Surname: 'Wellbeck', Country: 'Great Britain', Gender: 'Female', Money:5000}, 
	{Name: 'Thanasis', Surname: 'Papathanasiou', Country: 'Greece',Gender: 'Male', Money: 3200},
	{Name: 'George', Surname: 'Washington', Country: 'Great Britain', Gender: 'Male',Money:4200}, 
	{Name: 'Orfeas', Surname: 'Kalaitzis', Country: 'Greece', Gender: 'Male', Money: 7643}, 
    {Name: 'Nick', Surname: 'Wellington', Country: 'USA', Gender: 'Male', Money:1000}, 
	{Name: 'Kostas', Surname: 'Antoniou', Country: 'Greece', Gender: 'Male', Money: 8712},
	{Name: 'John', Surname: 'Oneal', Country: 'USA', Gender: 'Male', Money:98234}, 
	{Name: 'Paulos', Surname: 'Stamou', Country: 'Greece',  Gender: 'Male', Money: 3422}, 
    {Name: 'Soula', Surname: 'Spuropoulou', Country: 'Greece', Gender: 'Female', Money:400}, 
	{Name: 'Paul', Surname: 'Pierce', Country: 'USA',  Gender: 'Male',Money: 13000},
	{Name: 'Helen', Surname: 'Smith', Country: 'Great Britain', Gender: 'Female', Money:1000}, 
	{Name: 'Cathrine', Surname: 'Bryant', Country: 'Great Britain', Gender: 'Female', Money: 8712},
	{Name: 'Jenny', Surname: 'Scalabrini', Country: 'USA', Gender: 'Female', Money:92214}];
  
const groupByProperties = ['Country', 'Gender'];
const groupResult =  groupBy( {Group: data, By: groupByProperties} );

console.log(groupResult);

Answer 8

    var arr = [
        {shape: 'square', color: 'red', used: 1, instances: 1},
        {shape: 'square', color: 'red', used: 2, instances: 1},
        {shape: 'circle', color: 'blue', used: 0, instances: 0},
        {shape: 'square', color: 'blue', used: 4, instances: 4},
        {shape: 'circle', color: 'red', used: 1, instances: 1},
        {shape: 'circle', color: 'red', used: 1, instances: 0},
        {shape: 'square', color: 'blue', used: 4, instances: 5},
        {shape: 'square', color: 'red', used: 2, instances: 1}
    ];


    result = [];

    arr.forEach(function (a) {
        if ( !this[a.color] && !this[a.shape] ) {
            this[a.color] = { color: a.color, shape: a.shape, used: 0, instances: 0 };
            result.push(this[a.color]);
        } 
        this[a.color].used += a.used;
        this[a.color].instances += a.instances;
    }, Object.create(null));

    console.log(result);


**Output:**
    [
  {
    "color": "red",
    "shape": "square",
    "used": 11,
    "instances": 9
  },
  {
    "color": "blue",
    "shape": "circle",
    "used": 4,
    "instances": 4
  }
]


    thats all perfetcly working.

     Enjoy your coding....

Answer 9

用户要求的ES6答案：

// To call this function:
// const result = this.toolBox.multipleGroupByArray(
//    dataArray, (property: IProperty) => [property.prop1, property.prop2, property.prop3]);

multipleGroupByArray(dataArray, groupPropertyArray) {
    const groups = {};
    dataArray.forEach(item => {
        const group = JSON.stringify(groupPropertyArray(item));
        groups[group] = groups[group] || [];
        groups[group].push(item);
    });
    return Object.keys(groups).map(function(group) {
        return groups[group];
    });
}

Answer 10

如果您希望按条件字段使用groupBy键，则这里是@Abbes答案的修改：

@Embeddable
public class UserSettingId implements Serializable {

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "setting")
    private Setting setting;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "user")
    private User user;

    public UserSettingId() {
    }

    public UserSettingId(Setting setting, User user) {
        this.setting = setting;
        this.user = user;
    }

    public Setting getSetting() {
        return setting;
    }

    public void setSetting(Setting setting) {
        this.setting = setting;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }


    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof UserSettingId)) return false;
        UserSettingId that = (UserSettingId) o;
        return setting.equals(that.setting) &&
                user.equals(that.user);
    }

    @Override
    public int hashCode() {
        return Objects.hash(setting, user);
    }
}

并像这样使用它：

function groupBy(array, f) {
    let groups = {};
    array.forEach((o) => {
        var group = f(o).join('-');
        groups[group] = groups[group] || [];
        groups[group].push(o);
    });
    return groups;
}

Answer 11

这是一个更通用的分组和求和功能，它接受对象数组，要进行分组的键数组和要求和的键数组。

function groupAndSum(arr, groupKeys, sumKeys){
  return Object.values(
    arr.reduce((acc,curr)=>{
      const group = groupKeys.map(k => curr[k]).join('-');
      acc[group] = acc[group] || Object.fromEntries(
         groupKeys.map(k => [k, curr[k]]).concat(sumKeys.map(k => [k, 0])));
      sumKeys.forEach(k => acc[group][k] += curr[k]);
      return acc;
    }, {})
  );
}

演示：

var arr = [
    {shape: 'square', color: 'red', used: 1, instances: 1},
    {shape: 'square', color: 'red', used: 2, instances: 1},
    {shape: 'circle', color: 'blue', used: 0, instances: 0},
    {shape: 'square', color: 'blue', used: 4, instances: 4},
    {shape: 'circle', color: 'red', used: 1, instances: 1},
    {shape: 'circle', color: 'red', used: 1, instances: 0},
    {shape: 'square', color: 'blue', used: 4, instances: 5},
    {shape: 'square', color: 'red', used: 2, instances: 1}
];
function groupAndSum(arr, groupKeys, sumKeys){
  return Object.values(
    arr.reduce((acc,curr)=>{
      const group = groupKeys.map(k => curr[k]).join('-');
      acc[group] = acc[group] || Object.fromEntries(groupKeys.map(k => [k, curr[k]]).concat(sumKeys.map(k => [k, 0])));
      sumKeys.forEach(k => acc[group][k] += curr[k]);
      return acc;
    }, {})
  );
}
const res = groupAndSum(arr, ['shape', 'color'], ['used', 'instances']);
console.log(res);

Answer 12

1.sumkeys 3.groupkeys

  var arr = [
    {shape: 'square', color: 'red', used: 1, instances: 1},
    {shape: 'square', color: 'red', used: 2, instances: 1},
    {shape: 'circle', color: 'blue', used: 0, instances: 0},
    {shape: 'square', color: 'blue', used: 4, instances: 4},
    {shape: 'circle', color: 'red', used: 1, instances: 1},
    {shape: 'circle', color: 'red', used: 1, instances: 0},
    {shape: 'square', color: 'red', used: 4, instances: 4},
    {shape: 'square', color: 'red', used: 2, instances: 2}
];
   function groupbykeys(arr, groupKeys, sumKeys){
    var   hash = Object.create(null),
       grouped = [];
      arr.forEach(function (o) {
       var key = groupKeys.map(function (k) { return o[k]; }).join('|');
         if (!hash[key]) {
           hash[key] = Object.keys(o).reduce((result, key)=> {
            result[key]=o[key]; 
            if(sumKeys.includes(key))
               result[key]=0;
            return result;
          }, { }); //map_(o) //{ shape: o.shape, color: o.color, used: 0, instances: 0 };
           grouped.push(hash[key]);
       }
       sumKeys.forEach(function (k) { hash[key][k] += o[k]; });
   });
     return grouped;
     }
   
   
var result=groupbykeys(arr,['shape','color'],['used','instances']);
console.log(result)