This question already has answers here:
How to group by and sum an array of objects? [duplicate]
(2 answers)
Sum JavaScript object propertyA values with the same object propertyB in an array of objects
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Group by, and sum, and generate an object for each array in JavaScript
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ES6 Implementation of Group By and SUM
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Javascript array of objects group and sum items
(4 answers)
Closed last year.
Sorry if this has been asked before, but I couldn't find a good example of what I'm trying to accomplish. Maybe I'm just not searching for the right thing. Please correct me if there's an explanation of this somewhere.
so let's says I have a data like this :
data = [
{"no":1,"location":"New York","transaction":3000},
{"no":2,"location":"Tokyo","transaction":3000},
{"no":3,"location":"New York","transaction":3000},
{"no":4,"location":"Amsterdam","transaction":3000},
{"no":5,"location":"Manchester","transaction":3000},
{"no":6,"location":"New York","transaction":3000},
{"no":7,"location":"Tokyo","transaction":3000},
{"no":8,"location":"Tokyo","transaction":3000},
{"no":9,"location":"New York","transaction":3000},
{"no":10,"location":"Amsterdam","transaction":3000}
]
what i wanted to is an output like this :
result = [
{"location":"New York","transaction":12000},
{"location":"Tokyo","transaction":9000},
{"location":"Amsterdam","transaction":6000}
{"location":"Manchester","transaction":3000}
]
so what i wanted to do is grouping the data based on location and sum the transaction where the location is same and push the data to another array. i don't know where to start, need some help to solve this or any suggestion to solve this using Javascript. thank you
Working Demo :
// Input array
const data = [
{"no":1,"location":"New York","transaction":3000},
{"no":2,"location":"Tokyo","transaction":3000},
{"no":3,"location":"New York","transaction":3000},
{"no":4,"location":"Amsterdam","transaction":3000},
{"no":5,"location":"Manchester","transaction":3000},
{"no":6,"location":"New York","transaction":3000},
{"no":7,"location":"Tokyo","transaction":3000},
{"no":8,"location":"Tokyo","transaction":3000},
{"no":9,"location":"New York","transaction":3000},
{"no":10,"location":"Amsterdam","transaction":3000}
];
// result array
const resultArr = [];
// grouping by location and resulting with an object using Array.reduce() method
const groupByLocation = data.reduce((group, item) => {
const { location } = item;
group[location] = group[location] ?? [];
group[location].push(item.transaction);
return group;
}, {});
// Finally calculating the sum based on the location array we have.
Object.keys(groupByLocation).forEach((item) => {
groupByLocation[item] = groupByLocation[item].reduce((a, b) => a + b);
resultArr.push({
'location': item,
'transaction': groupByLocation[item]
})
})
console.log(resultArr)
Related
This question already has answers here:
Split array into chunks
(73 answers)
Closed 6 days ago.
This post was edited and submitted for review 6 days ago.
I'm using arrayofArrays[0].push() inside a for loop in order to add an Object to the Array0 inside arrayofArrays.
Now I'd like that when Array0 has reached 2 element, the next element will be pushed to Array1, in order to achieve this situation:
var arrayofArrays = [[Obj0,Obj1],[Obj2,Obj3],[Obj4,Obj5], ...];
Sample code:
var arrayofArrays = [[]];
for(data in Data){
var Obj = {"field1":data[0], "field2":data[1], "field3":data[2] }
arrayofArrays[0].push(Obj); // need to pass to arrayofArrays[1] when arrayofArrays[0] has 2 Obj...
}
(I don't need to split an existing array, I'm adding Object to an array, and want them to split in sub-arrays while adding them)
Here is a functional programming approach to your question to unflatten an array:
const arr = Array.from(Array(6).keys()); // [0, 1, 2, 3...]
let t;
let arrOfArr = arr.map((v, idx) => {
if(idx % 2) {
return [t, v];
} else {
t = v;
return null;
}
}).filter(Boolean);
console.log({
arr,
arrOfArr,
});
Note: Array.from(Array(6).keys()) is just for demo. Replace this with any array of objects you like
This question already has answers here:
Group array items using object
(19 answers)
How can I group an array of objects by key?
(32 answers)
Closed last month.
I am trying to create a new array of objects by comparing two arrays.One array contains the ids to be compared and the other contains the dataset which should be compared with the first array are a new array of object must be created.
Let me explain this in detail
Consider array 1:
['1','2']
Array 2
[{name:'Linus',id:'1'},{name:'Anthony',id:'1'},{name:'Jake',id:'2'},{name:'Eva',id:'2'}]
What I am expecting as a output is:
[
{id:'1',users:[{name:'Linus',id:'1'},{name:'Anthony',id:'1'}]},
{id:'2',users:[{name:'Jake',id:'2'},{name:'Eva',id:'2'}
]
I am not sure what has to be done.
Something like this for example
const ids = ['1','2'];
const users = [{name:Linus,id:'1'},{name:Anthony,id:'1'},{name:Jake,id:'2'},{name:Eva,id:'2'}];
const groups = ids.map(id =>{
return {
id,
users: users.filter(u => u.id === id)
}
})
const groupBy = ['1','2'];
const data = [{name:'Linus',id:'1'},{name:'Anthony',id:'1'},{name:'Jake',id:'2'},{name:'Eva',id:'2'}];
const result = groupBy.map(id => {
return {
id,
users: data.filter(item => item.id == id),
}
})
console.log(result);
Try this code
This question already has answers here:
Sorting an array of objects by property values
(35 answers)
How to sort strings in JavaScript
(16 answers)
Sort Array by ISO 8601 date
(8 answers)
Closed last year.
I have the following nested object. I would like to iterate through every item (latest.sentTime) and then sort the object itself by "sentTime". So that the most recent message is on top. How can I achieve this?
In the following example, "0" and "1" need to be swapped basically, since "1" has a more recent "sentTime".
Using Array#map, iterate over the array to get latest.sentTime
Using Array#sort and Date, sort the items
const arr = [
{ latest: { sentTime: '2022-02-05T19:15:32.000Z' } },
{ latest: { sentTime: '2022-02-06T22:12:00.000Z' } }
];
const sentTimes = arr
.map(({ latest }) => latest.sentTime)
.sort((a, b) => new Date(b) - new Date(a));
console.log(sentTimes);
This question already has answers here:
Get all unique values in a JavaScript array (remove duplicates)
(91 answers)
Closed 1 year ago.
I have this array of objects, my aim is to remove dublicate values from values array, I want the result to be [{name:'test1', values:['35,5', '35,2','35,3']}, {name:'test2', values:['33,2', '34,3', '32,5']}]
I have tried following solution but it does not works, Do you have any suggestions? Thanks in advance
let arr = [{name:'test1', values:['35,5', '35,2', '35,2', '35,3', '35,5']},
{name:'test2', values:['35,1', '35,1', '33,2', '34,3', '32,5']}]
let uniqueArray = arr.values.filter(function(item, pos) {
return arr.values.indexOf(item.values) == pos;
})
console.log(uniqueArray)
}
}
You can easily remove duplicates from an Array by creating a new Set based off it.
Set objects are collections of values. You can iterate through the elements of a set in insertion order. A value in the Set may only occur once; it is unique in the Set's collection
If you want the result in an array, just use spread syntax for that, for example:
let arr = [{
name: 'test1',
values: ['35,5', '35,2', '35,2', '35,3', '35,5']
},
{
name: 'test2',
values: ['35,1', '35,1', '33,2', '34,3', '32,5']
}
];
const uniqueArr = arr.reduce((accum, el) => {
// Copy all the original object properties to a new object
const obj = {
...el
};
// Remove the duplicates from values by creating a Set structure
// and then spread that back into an empty array
obj.values = [...new Set(obj.values)];
accum.push(obj);
return accum;
}, []);
uniqueArr.forEach(el => console.dir(el));
This question already has answers here:
How can I group an array of objects by key?
(32 answers)
Create Multilevel groups from an Array of Objects
(2 answers)
Closed 4 years ago.
var data=[
{custType:1,code:'savings',efDate:'2/3/19',exDate'2/3/19'},
{custType:1,code:'savings',efDate:'2/3/19',exDate:'2/3/19'},
{custType:1,code:'savings',efDate:'2/3/19',exDate:'2/3/19'},
{custType:1,code:'current',efDate:'2/3/19',exDate:'2/3/19'},
{custType:2,code:'current',efDate:'2/3/19',exDate:'2/3/19'},
{custType:2,code:'savings',efDate:'2/3/19',exDate:'2/3/19'},
{custType:2,code:'savings',efDate:'2/3/19',exDate:'2/3/19'}
];
expected results
var modifiedData=[
[
savings=[ {custType:1,code:'savings',efDate:'2/3/19',exDate:'2/3/19'},
{custType:1,code:'savings',efDate:'2/3/19',exDate:'2/3/19'},
{custType:1,code:'savings',efDate:'2/3/19',exDate:'2/3/19'}
],
current=[ {custType:1,code:'current',efDate:'2/3/19',exDate:'2/3/19'} ]
],
[
savings=[ {custType:2,code:'savings',efDate:'2/3/19',exDate:'2/3/19'},
{custType:2,code:'savings',efDate:'2/3/19',exDate:'2/3/19'} ],
current=[ {custType:2,code:'current',efDate:'2/3/19',exDate:'2/3/19'} ]
]
];
as i am trying to find a group with (custType and code), i am not able to generate the expected result. Which method i should use here? can i use reduce or groupBy. I am confused about it.
You could build up a nested hashtable:
const hash = {};
for(const value of data) {
const group = hash[value.custType] || (hash[value.custType] = {});
const group2 = group[value.code] || (group[value.code] = []);
group2.push(value);
}
const result = Object.values(hash).map(Object.values);