Tips for manipulating deeply nested arrays of objects within an array with JavaScript

Question

Tips for manipulating deeply nested arrays of objects within an array with JavaScript

I need assistance with calculating the average of ratings within nested array objects that are inside another array. Below is the array provided:

    let arr = [
[{"category":"behavioural", "rating":3}, {"category":"technical", "rating":4.5}],
[{"category":"behavioural", "rating":1}, {"category":"technical", "rating":2.5}],
[{"category":"behavioural", "rating":4}, {"category":"technical", "rating":2}]
]

The goal is to compute the average rating for each category and then save it in an object.

Desired outcome:

"metricsaverage" : {
    "behavioral" : 2.66,
    "technical" : 3
}

In this output, 2.66 and 3 represent the average ratings of all items belonging to their respective categories from the nested array of objects.

javascript arrays object

Answer 1

Answer №1

Code Example:

// Sample input array
let data = [
[{"type":"fruit", "price":3}, {"type":"vegetable", "price":5}],
[{"type":"fruit", "price":2}, {"type":"vegetable", "price":4}],
[{"type":"fruit", "price":4}, {"type":"vegetable", "price":6}]
];

// Convert multi-dimensional array into single dimension
let flattenedArray = [].concat(...data);

// Grouping by type and creating an object using Array.reduce() function
const groupByType = flattenedArray.reduce((group, item) => {
  const { type } = item;
  group[type] = group[type] ?? [];
  group[type].push(item.price);
  return group;
}, {});

// Calculate the average price based on the type array
Object.keys(groupByType).forEach((item) => {
    const len = groupByType[item].length;
    groupByType[item] = groupByType[item].reduce((a, b) => a + b)/len;
})

// Output the result
console.log(groupByType);

Answer 2

Code Example:

// Sample input array
let data = [
[{"type":"fruit", "price":3}, {"type":"vegetable", "price":5}],
[{"type":"fruit", "price":2}, {"type":"vegetable", "price":4}],
[{"type":"fruit", "price":4}, {"type":"vegetable", "price":6}]
];

// Convert multi-dimensional array into single dimension
let flattenedArray = [].concat(...data);

// Grouping by type and creating an object using Array.reduce() function
const groupByType = flattenedArray.reduce((group, item) => {
  const { type } = item;
  group[type] = group[type] ?? [];
  group[type].push(item.price);
  return group;
}, {});

// Calculate the average price based on the type array
Object.keys(groupByType).forEach((item) => {
    const len = groupByType[item].length;
    groupByType[item] = groupByType[item].reduce((a, b) => a + b)/len;
})

// Output the result
console.log(groupByType);

Answer 3

Answer №2

Check out this live demonstration: https://jsfiddle.net/galeroy/ot1pkvqg/4/

  let data = [
      [{"category":"behavioral", "rating":3}, {"category":"technical", "rating":4.5}],
      [{"category":"behavioral", "rating":1}, {"category":"technical", "rating":2.5}],
      [{"category":"behavioral", "rating":4}, {"category":"technical", "rating":2}]
    ]

    var behavioralTotal = 0,
        behavioralItems = 0,
        technicalTotal = 0,
        technicalItems = 0;

    data.forEach(function(set){         
      set.forEach(function(item){
        if(item.category === 'behavioral'){
          behavioralTotal += item.rating;
          behavioralItems++;
        }
        else if (item.category === 'technical')
        {
          technicalTotal += item.rating;
          technicalItems++
        }
      })
    });

    console.log(
      'metricsaverage = { \n' +
        '"behavioral" : ' + (behavioralTotal/behavioralItems).toFixed(2) + ',\n' +
        '"technical" : ' + (technicalTotal/technicalItems).toFixed(2) + '\n' +
      '}'
    )

Answer 4

Check out this live demonstration: https://jsfiddle.net/galeroy/ot1pkvqg/4/

  let data = [
      [{"category":"behavioral", "rating":3}, {"category":"technical", "rating":4.5}],
      [{"category":"behavioral", "rating":1}, {"category":"technical", "rating":2.5}],
      [{"category":"behavioral", "rating":4}, {"category":"technical", "rating":2}]
    ]

    var behavioralTotal = 0,
        behavioralItems = 0,
        technicalTotal = 0,
        technicalItems = 0;

    data.forEach(function(set){         
      set.forEach(function(item){
        if(item.category === 'behavioral'){
          behavioralTotal += item.rating;
          behavioralItems++;
        }
        else if (item.category === 'technical')
        {
          technicalTotal += item.rating;
          technicalItems++
        }
      })
    });

    console.log(
      'metricsaverage = { \n' +
        '"behavioral" : ' + (behavioralTotal/behavioralItems).toFixed(2) + ',\n' +
        '"technical" : ' + (technicalTotal/technicalItems).toFixed(2) + '\n' +
      '}'
    )

Tips for manipulating deeply nested arrays of objects within an array with JavaScript

Answer №1

Answer №2

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