Utilizing lodash for effective grouping

Question

Utilizing lodash for effective grouping

I have a collection of objects that looks like this:

var information = [
  {
    "quantity": 1, 
    "make": "ALFA ROMEO", 
    "model": "GIULIETTA DIESEL - 2010"
  }, 
  {
    "quantity": 2, 
    "make": "AUDI", 
    "model": "A1 DIESEL"
  }, 
  {
    "quantity": 1, 
    "make": "AUDI", 
    "model": "A1 SPORTBACK DIESEL"
  }, 
  {
    "quantity": 2, 
    "make": "AUDI", 
    "model": "A3 DIESEL - 2012"
  }, 
  {
    "quantity": 3, 
    "make": "Volkswagen", 
    "model": "Golf"
  }, 
  {
    "quantity": 3, 
    "make": "Ford", 
    "model": "Escord"
  }, 
  {
    "quantity": 2, 
    "make": "Opel", 
    "model": "Zafira"
  }
]

I am looking to group by the data based on the make attribute and then identify the top three makes with the highest quantity. Any remaining makes will be categorized as "Other".

An example output I desire is:

var result = [
    {
       "brand": "Audi",
       "count": 5
     },
     {
       "brand": "Volkswagen",
       "count": 3
     },
     {
       "brand": "Ford",
       "count": 3
     },
     {
       "brand": "Other",
       "count": 3
     }
]

I'm seeking guidance on how to approach this task. Any suggestions?

javascript lodash

Answer 1

Answer №1

How to Group and Sum Data in JavaScript

To group and sum data using lodash, start by initiating a chain with _.groupBy() based on the make. Next, use _.map() to map the results and then utilize _.sumBy() to sum the 'count' properties. Convert back to an array with _.values(), sort it in descending order using _.orderBy(), and finalize the chain with _.value(). Split the results into 2 arrays and calculate the sum of the 2nd array (the lowest counts) using reduce:

var data = [{"count":1,"make":"ALFA ROMEO","model":"GIULIETTA DIESEL - 2010"},{"count":2,"make":"AUDI","model":"A1 DIESEL"},{"count":1,"make":"AUDI","model":"A1 SPORTBACK DIESEL"},{"count":2,"make":"AUDI","model":"A3 DIESEL - 2012"},{"count":3,"make":"Volkswagen","model":"Golf"},{"count":3,"make":"Ford","model":"Escord"},{"count":2,"make":"Opel","model":"Zafira"}];

var counts = _(data)
  .groupBy('make')
  .map(function(g, key) { return {
      make: key,
      count: _.sumBy(g, 'count')
  };})
  .values()
  .orderBy('count', 'desc')
  .value();
  
var result = counts.slice(0, 3).concat({
  brand: 'other',
  count: counts.slice(3).reduce(function(s, { count }) { return s + count; }, 0)
})
  
console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

Using ES6

If you prefer using ES6, iterate through the data with Array#reduce, gather all the make count values into a Map, retrieve the map values iterator, spread them to obtain an array, and then sort it in descending order. Divide the results into 2 arrays and calculate the sum of the 2nd array (the lowest counts) using reduce:

const data = [{"count":1,"make":"ALFA ROMEO","model":"GIULIETTA DIESEL - 2010"},{"count":2,"make":"AUDI","model":"A1 DIESEL"},{"count":1,"make":"AUDI","model":"A1 SPORTBACK DIESEL"},{"count":2,"make":"AUDI","model":"A3 DIESEL - 2012"},{"count":3,"make":"Volkswagen","model":"Golf"},{"count":3,"make":"Ford","model":"Escord"},{"count":2,"make":"Opel","model":"Zafira"}];

const counts = [...data.reduce((m, { make, count }) => {
  const item = m.get(make) || { make, count: 0 };
  
  item.count += count;

  return m.set(make,  item);
}, new Map()).values()].sort((a, b) => b.count - a.count);

const result = counts.slice(0, 3).concat({
  brand: 'other',
  count: counts.slice(3).reduce((s, { count }) => s + count, 0)
})

console.log(result);

Answer 2

How to Group and Sum Data in JavaScript

To group and sum data using lodash, start by initiating a chain with _.groupBy() based on the make. Next, use _.map() to map the results and then utilize _.sumBy() to sum the 'count' properties. Convert back to an array with _.values(), sort it in descending order using _.orderBy(), and finalize the chain with _.value(). Split the results into 2 arrays and calculate the sum of the 2nd array (the lowest counts) using reduce:

var data = [{"count":1,"make":"ALFA ROMEO","model":"GIULIETTA DIESEL - 2010"},{"count":2,"make":"AUDI","model":"A1 DIESEL"},{"count":1,"make":"AUDI","model":"A1 SPORTBACK DIESEL"},{"count":2,"make":"AUDI","model":"A3 DIESEL - 2012"},{"count":3,"make":"Volkswagen","model":"Golf"},{"count":3,"make":"Ford","model":"Escord"},{"count":2,"make":"Opel","model":"Zafira"}];

var counts = _(data)
  .groupBy('make')
  .map(function(g, key) { return {
      make: key,
      count: _.sumBy(g, 'count')
  };})
  .values()
  .orderBy('count', 'desc')
  .value();
  
var result = counts.slice(0, 3).concat({
  brand: 'other',
  count: counts.slice(3).reduce(function(s, { count }) { return s + count; }, 0)
})
  
console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

Using ES6

If you prefer using ES6, iterate through the data with Array#reduce, gather all the make count values into a Map, retrieve the map values iterator, spread them to obtain an array, and then sort it in descending order. Divide the results into 2 arrays and calculate the sum of the 2nd array (the lowest counts) using reduce:

const data = [{"count":1,"make":"ALFA ROMEO","model":"GIULIETTA DIESEL - 2010"},{"count":2,"make":"AUDI","model":"A1 DIESEL"},{"count":1,"make":"AUDI","model":"A1 SPORTBACK DIESEL"},{"count":2,"make":"AUDI","model":"A3 DIESEL - 2012"},{"count":3,"make":"Volkswagen","model":"Golf"},{"count":3,"make":"Ford","model":"Escord"},{"count":2,"make":"Opel","model":"Zafira"}];

const counts = [...data.reduce((m, { make, count }) => {
  const item = m.get(make) || { make, count: 0 };
  
  item.count += count;

  return m.set(make,  item);
}, new Map()).values()].sort((a, b) => b.count - a.count);

const result = counts.slice(0, 3).concat({
  brand: 'other',
  count: counts.slice(3).reduce((s, { count }) => s + count, 0)
})

console.log(result);

Answer 3

Answer №2

To achieve this task, you can utilize a combination of lodash's groupBy and sumBy functions.

let result = _.chain(data)
        .groupBy("make")
        .map((element, id) => ({
            make: id,
            count: _.sumBy(element, 'count'),
        }))
        .value();

console.log(result);

[
  {
    "make": "ALFA ROMEO",
    "count": 1
  },
  {
    "make": "AUDI",
    "count": 5
  },
  {
    "make": "Volkswagen",
    "count": 3
  },
  {
    "make": "Ford",
    "count": 3
  },
  {
    "make": "Opel",
    "count": 2
  }
]

Answer 4

To achieve this task, you can utilize a combination of lodash's groupBy and sumBy functions.

let result = _.chain(data)
        .groupBy("make")
        .map((element, id) => ({
            make: id,
            count: _.sumBy(element, 'count'),
        }))
        .value();

console.log(result);

[
  {
    "make": "ALFA ROMEO",
    "count": 1
  },
  {
    "make": "AUDI",
    "count": 5
  },
  {
    "make": "Volkswagen",
    "count": 3
  },
  {
    "make": "Ford",
    "count": 3
  },
  {
    "make": "Opel",
    "count": 2
  }
]

Answer 5

Answer №3

To achieve the desired outcome using vanilla JavaScript, one can implement a hash table to aggregate data based on the same 'make', followed by sorting the resulting array. The next step involves summing up all counts at the end of the result set until reaching the desired length.

var data = [{ count: 1, make: "ALFA ROMEO", model: "GIULIETTA DIESEL - 2010" }, { count: 2, make: "AUDI", model: "A1 DIESEL" }, { count: 1, make: "AUDI", model: "A1 SPORTBACK DIESEL" }, { count: 2, make: "AUDI", model: "A3 DIESEL - 2012" }, { count: 3, make: "Volkswagen", model: "Golf" }, { count: 3, make: "Ford", model: "Escord" }, { count: 2, make: "Opel", model: "Zafira" }],
    hash = Object.create(null),
    result = [];

data.forEach(function (car) {
    if (!hash[car.make]) {
        hash[car.make] = { make: car.make, count: 0 };
        result.push(hash[car.make]);
    }
    hash[car.make].count += car.count;
});

result.sort(function (a, b) {
    return b.count - a.count;
});

while (result.length > 4) {
    result.push({ make: 'Other', count: result.pop().count + result.pop().count });
}

console.log(result);

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

Answer 6

To achieve the desired outcome using vanilla JavaScript, one can implement a hash table to aggregate data based on the same 'make', followed by sorting the resulting array. The next step involves summing up all counts at the end of the result set until reaching the desired length.

var data = [{ count: 1, make: "ALFA ROMEO", model: "GIULIETTA DIESEL - 2010" }, { count: 2, make: "AUDI", model: "A1 DIESEL" }, { count: 1, make: "AUDI", model: "A1 SPORTBACK DIESEL" }, { count: 2, make: "AUDI", model: "A3 DIESEL - 2012" }, { count: 3, make: "Volkswagen", model: "Golf" }, { count: 3, make: "Ford", model: "Escord" }, { count: 2, make: "Opel", model: "Zafira" }],
    hash = Object.create(null),
    result = [];

data.forEach(function (car) {
    if (!hash[car.make]) {
        hash[car.make] = { make: car.make, count: 0 };
        result.push(hash[car.make]);
    }
    hash[car.make].count += car.count;
});

result.sort(function (a, b) {
    return b.count - a.count;
});

while (result.length > 4) {
    result.push({ make: 'Other', count: result.pop().count + result.pop().count });
}

console.log(result);

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

Utilizing lodash for effective grouping

Answer №1

Answer №2

Answer №3

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