按数组中的多个属性对对象进行分组，然后将它们的值相加
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【中文标题】按数组中的多个属性对对象进行分组，然后将它们的值相加【英文标题】：Group objects by multiple properties in array then sum up their values 【发布时间】：2018-03-29 09:16:31 【问题描述】：Grouping elements in array by multiple properties 是与我的问题最接近的匹配项，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套在一个二维数组中。
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
];
仅当 shape 和 color 相同时，此数组中的对象才被视为重复对象。如果是，我想分别总结它们的used 和instances 值，然后删除重复项。
所以在这个例子中，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);但它输出
[shape: "square", color: "red", used: 11, instances: 9,
shape: "circle", color: "blue", used: 4, instances: 4]
而不是预期的结果：
[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]
如何让我的函数按形状和颜色正确分组对象？即总结它们的值并删除重复项？
【问题讨论】：
您可以使用其他问题中的解决方案，然后在最后遍历数组并将子数组中的used 和instances 相加。
您可以遍历数组并使用字符串“shape|color”作为对象的属性。
优秀的工作完美......实际上我找到了很多方法终于从你的代码中得到了解决方案......非常感谢......
【参考方案1】：
将Array#reduce 与辅助对象一起使用以对相似对象进行分组。对于每个对象，检查组合的 shape 和 color 是否存在于帮助程序中。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);【讨论】：
为什么在下面的示例中使用地图？与使用普通 作为基础减少值相比，这提供了哪些好处？最后返回Object.values(theObject)。谢谢。
如果我没记错的话，这个答案是在Object.values() 不完全支持（或者我不知道这种支持）时创建的。此外，使用 Map 比对象具有优势 - Map 将始终保留条目的顺序。如果键是整数（此处不是这种情况），则 Map 将保留条目顺序，而对象将按升序排列键。
此外，Map 将支持所有类型的键，而对象仅支持字符串键（非字符串转换为字符串）。【参考方案2】：
使用此方法指定多个属性：
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];
)
像这样调用这个方法：
var result = Utils.groupBy(arr, function (item)
return [item.shape, item.color];
);
【讨论】：
这非常有效。我必须按 4 个不同的属性进行分组，并且经过一些修改以使其达到 ES6 标准，它可以完美运行！ @AlfaBravo 你能否分享 ES6 版本作为单独的答案【参考方案3】：您可以使用哈希表和键对相同的组进行分组。
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);.as-console-wrapper max-height: 100% !important; top: 0; 【讨论】：
【参考方案4】：您可以使用reduce() 创建一个具有唯一shape|color 属性的对象，并使用Object.values() 返回这些值的数组。
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]
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)【讨论】：
【参考方案5】：用户要求的 ES6 回答：
// 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];
);
【讨论】：
【参考方案6】：这是一个更通用的分组和求和函数，它接受一个对象数组、一个要分组的键数组和一个要求和的键数组。
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);【讨论】：
代码按预期工作正常，而且它也是动态的。如果我在数组中的任何值都是NAN（用于sumKeys），如何在代码中处理？【参考方案7】：如果您希望根据条件字段使用 groupBy 键，那么这里是 @Abbes 答案的修改：
function groupBy(array, f)
let groups = ;
array.forEach((o) =>
var group = f(o).join('-');
groups[group] = groups[group] || [];
groups[group].push(o);
);
return groups;
并像这样使用它：
groupBy(connectedServers, (item) =>
return [item.key1, item.key2];
);
【讨论】：
【参考方案8】：如果您需要基于颜色或形状属性的“已使用”和“实例”数组；那么你可以使用这个代码。
（PS：我知道这不是您想要的，但将来它可能会对某人有所帮助。也为此目的重用Nenand's 代码。如果代码对您有用，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);
输出会是这样的
【讨论】：
【参考方案9】：我有一个建议给你。 如果你想让它更容易做，你可以试试 Underscore 库：http://underscorejs.org/
我很快尝试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，然后您可以做任何您想做的事情，例如，按照您的意愿计算数据。
也许你可以优化它，如果你需要更多帮助，请告诉我
【讨论】：
【参考方案10】：/**
* 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个人和所拥有金钱的信息。我们想为所有具有相同国籍和相同性别的人汇总这笔钱。
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)
所以，我们得到了 6 个数组。每个数组按Country 和Gender 分组
遍历每个数组，我们可以总结出钱！
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);【讨论】：
最好能解释一下为什么这是解决方案，而不是仅仅发布一些代码【参考方案11】： 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....
【讨论】：
【参考方案12】：1.sumkeys 3.组键
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)【讨论】：
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