How to sum object values by a key value that is an date object?

Question

I try to sum all "Menge" and "Fehler" values if the "Datum" is the same. The probelmm is that "Datum" is a date object.

var arr = [{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":100,"Fehler":5},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":5,"Fehler":1},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":6,"Fehler":65},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"222","Menge":10,"Fehler":5},{"Datum":{"date":"2000-01-02 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"444","Menge":29,"Fehler":1},{"Datum":{"date":"2000-01-02 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":1,"Fehler":1}]

console.log(arr)
var holder = {};

arr.forEach(function (d) {
    if (holder.hasOwnProperty(d.Datum)) {
        holder[d.Datum] = holder[d.Datum] + d.Menge;
    } else {
        holder[d.Datum] = d.Menge;
    }
});

var obj2 = [];

for (var prop in holder) {
    obj2.push({
        Datum: prop,
        Menge: holder[prop]
    });
}

console.log(obj2);

But the result should be:

[
  {
    "Datum": "2000-01-01",
    "Menge": 121,
    "Fehler": 76
  },
  {
    "Datum": "2000-01-02",
    "Menge": 30,
    "Fehler": 2
  }
]

A1exandr Belan · Accepted Answer · 2022-01-13 12:58:03Z

1

Kind of ES6 way and grouping by hash solution:

const arr = [{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":100,"Fehler":5},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":5,"Fehler":1},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":6,"Fehler":65},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"222","Menge":10,"Fehler":5},{"Datum":{"date":"2000-01-02 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"444","Menge":29,"Fehler":1},{"Datum":{"date":"2000-01-02 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":1,"Fehler":1}]

const result = Object.values(arr.reduce((acc, obj) => {
  const [Datum] = obj.Datum.date.split(' ');
  const Menge = (acc[Datum]?.Menge + obj.Menge) || obj.Menge;
  const Fehler = (acc[Datum]?.Fehler + obj.Fehler) || obj.Fehler;
  const Ratio = Fehler / Menge;
  acc[Datum] = { Datum, Menge, Fehler, Ratio };
  return acc;
}, {}));

console.log(result);

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edited Jan 13, 2022 at 12:58

answered Jan 13, 2022 at 11:45

A1exandr Belan

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6 Comments

InFlames82 Over a year ago

thank you. an additional question: How do I create additional to "Menge" and "Fehler" an new key "ratio" where I calculate the ratio of Fehler/Menge? I don't know how to access Menge and Fehler values in your code to calculate the ratio.

A1exandr Belan Over a year ago

@InFlames82 Happy to help! Check updated code with ratio property

InFlames82 Over a year ago

Thank you! But I have one more question. How do I calculate the values when not only "Datum" but a second key must match? For example "Datum" and "Material" must be the same?

A1exandr Belan Over a year ago

@InFlames82 You can extend the hash to group by multiple fields. Look at this answer for example. This solution filters the array by two criteria, but approach will be the same.

InFlames82 Over a year ago

I create a new question for this. stackoverflow.com/q/70708103/10474530

|

Udith Gunaratna · Accepted Answer · 2022-01-13 11:12:36Z

1

If you ignore the timezone and the time part, you can just extract the date part as below and use it as the key for holder.

var arr = [{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":100,"Fehler":5},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":5,"Fehler":1},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":6,"Fehler":65},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"222","Menge":10,"Fehler":5},{"Datum":{"date":"2000-01-02 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"444","Menge":29,"Fehler":1},{"Datum":{"date":"2000-01-02 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":1,"Fehler":1}]

var holder = {};

arr.forEach(function (d) {
const dateStr = d.Datum.date.substring(0, 10);

  if (holder.hasOwnProperty(dateStr)) {
    var existing = holder[dateStr];
    holder[dateStr] = {
        Datum: dateStr,
        Menge: existing.Menge + d.Menge,
        Fehler: existing.Fehler + d.Fehler,
    };
  } else {
    holder[dateStr] = {
        Datum: dateStr,
        Menge: d.Menge,
        Fehler: d.Fehler,
    };
  }
});

var obj2 = Object.values(holder);
console.log(obj2);

edited Jan 13, 2022 at 11:12

answered Jan 13, 2022 at 11:07

Udith Gunaratna

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2 Comments

InFlames82 Over a year ago

Thank you! But what about the "Fehler" sum? You can see it in my example result.

Udith Gunaratna Over a year ago

Updated the code to include "Fehler" sum and also removed the need for 2nd loop

cacalonga · Accepted Answer · 2022-01-13 12:04:17Z

Alternative way;

var arr = [{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":100,"Fehler":5},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":5,"Fehler":1},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":6,"Fehler":65},{"Datum":{"date":"2000-01-01 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"222","Menge":10,"Fehler":5},{"Datum":{"date":"2000-01-02 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"444","Menge":29,"Fehler":1},{"Datum":{"date":"2000-01-02 00:00:00.000000","timezone_type":3,"timezone":"Europe/Berlin"},"Material":"123","Menge":1,"Fehler":1}]

var Arrr = [];

arr.forEach(function (d) {
var dateArr = d.Datum.date.split(" ");
if(Arrr.find(x=> x.Datum ===dateArr[0]))
{
    Arrr.find(x=> x.Datum ===dateArr[0]).Fehler += d.Fehler;
    Arrr.find(x=> x.Datum ===dateArr[0]).Menge += d.Menge;
}
else {
    Arrr.push({
        Datum: dateArr[0],
        Menge: d.Menge,
        Fehler:d.Fehler
    });
}
});

console.log(Arrr);

PZBird · Accepted Answer · 2022-01-13 11:18:27Z

Alternative, if your timezone has influence, you can stringify your Datum, like this:

var arr = [{ "Datum": { "date": "2000-01-01 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "123", "Menge": 100, "Fehler": 5 }, { "Datum": { "date": "2000-01-01 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "123", "Menge": 5, "Fehler": 1 }, { "Datum": { "date": "2000-01-01 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "123", "Menge": 6, "Fehler": 65 }, { "Datum": { "date": "2000-01-01 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "222", "Menge": 10, "Fehler": 5 }, { "Datum": { "date": "2000-01-02 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "444", "Menge": 29, "Fehler": 1 }, { "Datum": { "date": "2000-01-02 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "123", "Menge": 1, "Fehler": 1 }]

var holder = new Map();

arr.forEach(function (d) {
  const strDatum = JSON.stringify(d.Datum);
  const current = holder.get(strDatum) || { Menge: 0, Fehler: 0};

  holder.set(strDatum, { Menge: current.Menge + d.Menge, Fehler: current.Fehler + d.Fehler });
});

var obj2 = [];

holder.forEach((value, key) => {
  obj2.push({
    Datum: JSON.parse(key),
    Menge: value.Menge,
    Fehler: value.Fehler,
  });
});

console.log(obj2);

Alok · Accepted Answer · 2022-01-13 12:01:01Z

Without Using JS split() or substring()

Use Date() to get your defined results. I have just a suggestion on top of Udith answer. You can do some thing like this:

// This can easily give you the results without even worrying for any substring stuff
const date = new Date(obj.Datum.date)

Final Code:

var dataArray = [{ "Datum": { "date": "2000-01-01 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "123", "Menge": 100, "Fehler": 5 }, { "Datum": { "date": "2000-01-01 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "123", "Menge": 5, "Fehler": 1 }, { "Datum": { "date": "2000-01-01 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "123", "Menge": 6, "Fehler": 65 }, { "Datum": { "date": "2000-01-01 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "222", "Menge": 10, "Fehler": 5 }, { "Datum": { "date": "2000-01-02 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "444", "Menge": 29, "Fehler": 1 }, { "Datum": { "date": "2000-01-02 00:00:00.000000", "timezone_type": 3, "timezone": "Europe/Berlin" }, "Material": "123", "Menge": 1, "Fehler": 1 }];

const holder = {};

dataArray.forEach(obj => {
  // Using Date() of Javascript for converting the timestamp to a 
  // a date object for better computation
  const objDate = new Date(obj.Datum.date);
  if(holder.hasOwnProperty(objDate)){
    let existingData = holder[objDate];
    holder[objDate] = {
        Datum: obj.Datum.date,
        Menge: existingData.Menge + obj.Menge,
        Fehler: existingData.Fehler + obj.Fehler
    };
  }else{
    holder[objDate] = {
      Datum: obj.Datum.date,
      Menge: obj.Menge,
      Fehler: obj.Fehler
    }
  }
});

const resultObj = Object.values(holder);
console.log(resultObj);

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