JavaScript's sequential addition of nested arrays

Question

JavaScript's sequential addition of nested arrays

Having trouble adding together 4 nested arrays in JavaScript. The arrays are structured like this: x = [[Array1(9)], [Array2(9)], [Array3(9)], [Array4(9)]]

I am looking to "zip" them together and add the values. For example, I want to add Array1[0] with corresponding elements of Array2-4[0], and do this for all nine values in each array.

The arrays look like this:

[1, 2, 4, 3.6, 1.05, 4.65, 1.95, 0.5, 2.5]

[0.432, 0.602, 1.29, 1.146, 0.558, 1.43, 0.686, 0.178, 1.024]

The result would be something like:

[1.432, 2.602, etc...]

I've been struggling with using x.map() to accomplish this. Any assistance would be greatly appreciated.

Thank you,

javascript arrays multidimensional-array map-function array.prototype.map

Answer 1

Answer №1

If you want to iterate through the outer array, you can use Array.prototype.reduce() and then loop through each nested array using Array.prototype.forEach() to sum up the values of each nested array item with their corresponding items in the resulting array:

const src = [[1, 2, 4, 3.6, 1.05, 4.65, 1.95, 0.5, 2.5], [0.432, 0.602, 1.29, 1.146, 0.558, 1.43, 0.686, 0.178, 1.024]]

result = src.reduce((r,a) => (a.forEach((n,j) => r[j] = (r[j]||0)+n), r),[])

console.log(result)

.as-console-wrapper{min-height:100%;}

Answer 2

If you want to iterate through the outer array, you can use Array.prototype.reduce() and then loop through each nested array using Array.prototype.forEach() to sum up the values of each nested array item with their corresponding items in the resulting array:

const src = [[1, 2, 4, 3.6, 1.05, 4.65, 1.95, 0.5, 2.5], [0.432, 0.602, 1.29, 1.146, 0.558, 1.43, 0.686, 0.178, 1.024]]

result = src.reduce((r,a) => (a.forEach((n,j) => r[j] = (r[j]||0)+n), r),[])

console.log(result)

.as-console-wrapper{min-height:100%;}

Answer 3

Answer №2

Utilizing for each loop for both outer and inner arrays

let arrayOne = [ [1, 2, 4, 3.6, 1.05, 4.65, 1.95, 0.5, 2.5],[0.432, 0.602, 1.29, 1.146, 0.558, 1.43, 0.686, 0.178, 1.024]]
let arrayTwo = [];
arrayOne.forEach((arr) => arr.forEach((innerArr, index) => {
if (!arrayTwo[index]) arrayTwo[index] = 0; 
arrayTwo[index] = arrayTwo[index] + innerArr;
}));
console.log(arrayTwo);

Answer 4

Utilizing for each loop for both outer and inner arrays

let arrayOne = [ [1, 2, 4, 3.6, 1.05, 4.65, 1.95, 0.5, 2.5],[0.432, 0.602, 1.29, 1.146, 0.558, 1.43, 0.686, 0.178, 1.024]]
let arrayTwo = [];
arrayOne.forEach((arr) => arr.forEach((innerArr, index) => {
if (!arrayTwo[index]) arrayTwo[index] = 0; 
arrayTwo[index] = arrayTwo[index] + innerArr;
}));
console.log(arrayTwo);

Answer 5

Answer №3

Utilize the initial array as a map and add corresponding values from the other three arrays to each value. You can create a custom function, such as sumArrays, to handle arrays of any length.

const arrays = getData();
let sums = arrays[0].map((v, i) => v + arrays[1][i] + arrays[2][i] + arrays[3][i]);
let sums2 = sumArrays(arrays);

console.log(sums);
console.log(sums2);

function sumArrays(arrays) {
 const checkLengthEquality = () => {
  let lengths = arrays.map(v => v.length);
  return Math.max(...lengths) === Math.min(...lengths);
 };

 if (!checkLengthEquality()) {
  throw Error("Arrays are not of equal length");
 }
 
 const sum = (v, i) => {
  let len = arrays.length;
  while(len-- > 1) {
    v += arrays[len][i];
  }
  return v;
 };
 
 return arrays[0].map((v, i) => sum(v, i));
}

function getData() {
  return [
    [1, 2, 4, 3.6, 1.05, 4.65, 1.95, 0.5, 2.5], 
    [0.432, 0.602, 1.29, 1.146, 0.558, 1.43, 0.686, 0.178, 1.024],
    [3.1, 2, 4.3, 3.8, 1.5, 6.5, 95, 1.5, 2.5],
    [12, 1, 1.3, 8, 5.3, 6.2, 5, 1, 2.3]
  ];
}

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

Answer 6

Utilize the initial array as a map and add corresponding values from the other three arrays to each value. You can create a custom function, such as sumArrays, to handle arrays of any length.

const arrays = getData();
let sums = arrays[0].map((v, i) => v + arrays[1][i] + arrays[2][i] + arrays[3][i]);
let sums2 = sumArrays(arrays);

console.log(sums);
console.log(sums2);

function sumArrays(arrays) {
 const checkLengthEquality = () => {
  let lengths = arrays.map(v => v.length);
  return Math.max(...lengths) === Math.min(...lengths);
 };

 if (!checkLengthEquality()) {
  throw Error("Arrays are not of equal length");
 }
 
 const sum = (v, i) => {
  let len = arrays.length;
  while(len-- > 1) {
    v += arrays[len][i];
  }
  return v;
 };
 
 return arrays[0].map((v, i) => sum(v, i));
}

function getData() {
  return [
    [1, 2, 4, 3.6, 1.05, 4.65, 1.95, 0.5, 2.5], 
    [0.432, 0.602, 1.29, 1.146, 0.558, 1.43, 0.686, 0.178, 1.024],
    [3.1, 2, 4.3, 3.8, 1.5, 6.5, 95, 1.5, 2.5],
    [12, 1, 1.3, 8, 5.3, 6.2, 5, 1, 2.3]
  ];
}

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

JavaScript's sequential addition of nested arrays

Answer №1

Answer №2

Answer №3

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