Adding up nested arrays based on their respective indices

Question

Adding up nested arrays based on their respective indices

If I have two nested arrays within a corresponding array like this:

const nums = [
    [4, 23, 20, 23, 6, 8, 4, 0],      // Each array consists of 8 items
    [7, 5, 2, 2, 0, 0, 0, 0] 
];

How can I add the values based on their indexes?

Expected Result:

// For example: 11 is from 4 (array1 - index1) + 7 (array2 - index1)
// and so forth.
[11, 28, 22, 25, 6, 8, 4, 0]

This is what I tried:

// While this solution works for two arrays,
// it wouldn't be dynamic enough to handle more than two arrays

const total = Array.from({ length: 8 }, (_, i) => nums[0][i] + nums[1][i]);

javascript arrays typescript

Answer 1

Answer №1

This code snippet demonstrates the ability to handle nested arrays.

const arr = [
  [4, 23, 20, 23, 6, 8, 4, 0],
  [7, 5, 2, 2, 0, 0, 0, 0],
  [2, 1, 2, 5, 7, 8, 9, 4]
];


const sum = arr.reduce((a, b) => a.map((c, i) => c + b[i]));

console.log(sum);

Answer 2

This code snippet demonstrates the ability to handle nested arrays.

const arr = [
  [4, 23, 20, 23, 6, 8, 4, 0],
  [7, 5, 2, 2, 0, 0, 0, 0],
  [2, 1, 2, 5, 7, 8, 9, 4]
];


const sum = arr.reduce((a, b) => a.map((c, i) => c + b[i]));

console.log(sum);

Answer 3

Answer №2

Using the Array.map() method, we can transform each element of the first inner array into the sum of elements in the same column. To calculate the sum of elements in the same column, we employ the Array.reduce() function within the map():

const nums = [
  [4, 23, 20, 23, 6, 8, 4, 0],
  [7, 5, 2, 2, 0, 0, 0, 0],
  [1, 3, 4, 7, 1, 1, 1, 1],
];

let [first, ...rest] = nums;
let res = first.map((e, i) => rest.reduce((sum, x) => sum + x[i], e));

console.log(res);

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

Answer 4

Using the Array.map() method, we can transform each element of the first inner array into the sum of elements in the same column. To calculate the sum of elements in the same column, we employ the Array.reduce() function within the map():

const nums = [
  [4, 23, 20, 23, 6, 8, 4, 0],
  [7, 5, 2, 2, 0, 0, 0, 0],
  [1, 3, 4, 7, 1, 1, 1, 1],
];

let [first, ...rest] = nums;
let res = first.map((e, i) => rest.reduce((sum, x) => sum + x[i], e));

console.log(res);

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

Answer 5

Answer №3

You can implement a solution utilizing a nested forEach() loop

const values = [
    [4, 23, 20, 23, 6, 8, 4, 0],
    [7, 5, 2, 2, 0, 0, 0, 0] 
];

function calculateSum(array){
  let max = Math.max(...array.map(x => x.length));
  let result = Array(max).fill(0);
  result.forEach((x,i) => {
    values.forEach(subArray => {
      result[i] = result[i] + (subArray[i] || 0)
    })
  });
  return result;
}

console.log(calculateSum(values));

Answer 6

You can implement a solution utilizing a nested forEach() loop

const values = [
    [4, 23, 20, 23, 6, 8, 4, 0],
    [7, 5, 2, 2, 0, 0, 0, 0] 
];

function calculateSum(array){
  let max = Math.max(...array.map(x => x.length));
  let result = Array(max).fill(0);
  result.forEach((x,i) => {
    values.forEach(subArray => {
      result[i] = result[i] + (subArray[i] || 0)
    })
  });
  return result;
}

console.log(calculateSum(values));

Answer 7

Answer №4

To efficiently sum arrays by index, you can utilize the reduce method along with an inner loop in JavaScript. It's important to handle scenarios such as varying array lengths and non-numeric values.

const nums = [
    [4, 23, 20, 23, 6, 8, 4, 0],      // Each array consists of 8 items
    [7, 5, 2, 2, 0, 0, 0, 0] 
];
const otherNums = [
    [4, 23, 20, 23, 6, 8, 4, 0, 9, 55],      // Each array consists of 8 items
    [7, 5, 2, 2, 0, 0, 0, 0, "cat", null, 78],
    [7, 5, 2, 2, 0, 0, 0, 0, "dog", null, 78],
    [7, 5, 2, 2, 0, 0, 0, 0, "elephant", null, 78] 
];

const sumArraysByIndex = nums => nums.reduce((sums, array) => {
  for (const index in array) {
    if (sums[index] === undefined) sums[index] = 0
    if (isNaN(array[index])) return sums
    sums[index] += array[index]
  }
  return sums
}, [])

console.log(sumArraysByIndex(nums))
console.log(sumArraysByIndex(otherNums))

Answer 8

To efficiently sum arrays by index, you can utilize the reduce method along with an inner loop in JavaScript. It's important to handle scenarios such as varying array lengths and non-numeric values.

const nums = [
    [4, 23, 20, 23, 6, 8, 4, 0],      // Each array consists of 8 items
    [7, 5, 2, 2, 0, 0, 0, 0] 
];
const otherNums = [
    [4, 23, 20, 23, 6, 8, 4, 0, 9, 55],      // Each array consists of 8 items
    [7, 5, 2, 2, 0, 0, 0, 0, "cat", null, 78],
    [7, 5, 2, 2, 0, 0, 0, 0, "dog", null, 78],
    [7, 5, 2, 2, 0, 0, 0, 0, "elephant", null, 78] 
];

const sumArraysByIndex = nums => nums.reduce((sums, array) => {
  for (const index in array) {
    if (sums[index] === undefined) sums[index] = 0
    if (isNaN(array[index])) return sums
    sums[index] += array[index]
  }
  return sums
}, [])

console.log(sumArraysByIndex(nums))
console.log(sumArraysByIndex(otherNums))

Answer 9

Answer №5

Find the shortest length of a subarray and then generate an array of that size, adding up the values using their indexes.

const nums = [
    [4, 23, 20, 23, 6, 8, 4, 0],
    [7, 5, 2, 2, 0, 0, 0, 0]
];

const [arr1, arr2] = nums;
const min = Math.min(nums[0].length, nums[1].length);

const output = Array.from({length: min}, (_, i) => arr1[i] + arr2[i]);

console.log(output);

Answer 10

Find the shortest length of a subarray and then generate an array of that size, adding up the values using their indexes.

const nums = [
    [4, 23, 20, 23, 6, 8, 4, 0],
    [7, 5, 2, 2, 0, 0, 0, 0]
];

const [arr1, arr2] = nums;
const min = Math.min(nums[0].length, nums[1].length);

const output = Array.from({length: min}, (_, i) => arr1[i] + arr2[i]);

console.log(output);

Adding up nested arrays based on their respective indices

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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