What is the process for finding the total of numerous arrays?

Question

What is the process for finding the total of numerous arrays?

I need help solving an equation that involves adding numbers from a list of randomly generated arrays, following the indices.

Each array in the list consists of four fixed-length random numbers:

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1]
]

My goal is to calculate the sum of each number at every index across all arrays. For example:

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1]
]

// Expected Result: [8, 19, 18, 7];

Can you provide guidance on how to accomplish this task?

javascript arrays math

Answer 1

Answer №1

Using the `map()` method on the initial array, this code snippet showcases a unique approach by nesting it with the `reduce()` function to calculate the sum of each corresponding column.

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1]
];

const sums = list[0].map((x, idx) => list.reduce((sum, curr) => sum + curr[idx], 0));

console.log(sums);

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

Answer 2

Using the `map()` method on the initial array, this code snippet showcases a unique approach by nesting it with the `reduce()` function to calculate the sum of each corresponding column.

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1]
];

const sums = list[0].map((x, idx) => list.reduce((sum, curr) => sum + curr[idx], 0));

console.log(sums);

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

Answer 3

Answer №2

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1],
];

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

console.log(result);

Update: there was a request for an explanation.

To start off, the reduce function receives an array (of arrays) and aims to condense it into a single value (also an array). In order to achieve this, it executes the first arrow function twice. The initial call will have a as [2,9,1,2] and b as [2,3,9,4]. The first arrow function then operates on a and b, resulting in a map of a. Considering that a is an array, the output will be a new array where each element is summed with the corresponding element from array b. This outcome will be [4,12,10,6]. Subsequently, reduce proceeds to invoke the first arrow function again with the recent result of the map operation: [4,12,10,6] as a and the final array element from the input [4,7,8,1] as b. Similarly to before, this arrow function combines elements from both arrays, resulting in another array where each a element is added to its respective element in b. The subsequent map returns [8,19,18,7]. As all input elements have been utilized, reduce concludes by returning this final value (the array).

Answer 4

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1],
];

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

console.log(result);

Update: there was a request for an explanation.

To start off, the reduce function receives an array (of arrays) and aims to condense it into a single value (also an array). In order to achieve this, it executes the first arrow function twice. The initial call will have a as [2,9,1,2] and b as [2,3,9,4]. The first arrow function then operates on a and b, resulting in a map of a. Considering that a is an array, the output will be a new array where each element is summed with the corresponding element from array b. This outcome will be [4,12,10,6]. Subsequently, reduce proceeds to invoke the first arrow function again with the recent result of the map operation: [4,12,10,6] as a and the final array element from the input [4,7,8,1] as b. Similarly to before, this arrow function combines elements from both arrays, resulting in another array where each a element is added to its respective element in b. The subsequent map returns [8,19,18,7]. As all input elements have been utilized, reduce concludes by returning this final value (the array).

Answer 5

Answer №3

If you want to achieve the desired outcome, try using the following approach that involves utilizing two loops with forEach.

const blockList = [[2, 9, 1, 2], [2, 3, 9, 4], [4, 7, 8, 1]];
const result = [];

blockList.forEach((v, index) =>
  v.forEach((val, i) => {
    result[i] = result[i] ? result[i] : 0;
    result[i] += val;
  })
);

console.log(result);

Check out the code on CodePen - here

Answer 6

If you want to achieve the desired outcome, try using the following approach that involves utilizing two loops with forEach.

const blockList = [[2, 9, 1, 2], [2, 3, 9, 4], [4, 7, 8, 1]];
const result = [];

blockList.forEach((v, index) =>
  v.forEach((val, i) => {
    result[i] = result[i] ? result[i] : 0;
    result[i] += val;
  })
);

console.log(result);

Check out the code on CodePen - here

Answer 7

Answer №4

If you need to manipulate arrays in JavaScript, consider utilizing the reduce and forEach methods.

In this example, we create an array where specific elements are added to particular indexes, allowing us to extract values from the object efficiently.

const list = [[2, 9, 1, 2],[2, 3, 9, 4],[4, 7, 8, 1]]

let op = list.reduce((op,inp)=> {
    inp.forEach((e,i)=> op[i] = op[i] ? op[i]+e : e)
    return op
},[])

console.log(op)

Answer 8

If you need to manipulate arrays in JavaScript, consider utilizing the reduce and forEach methods.

In this example, we create an array where specific elements are added to particular indexes, allowing us to extract values from the object efficiently.

const list = [[2, 9, 1, 2],[2, 3, 9, 4],[4, 7, 8, 1]]

let op = list.reduce((op,inp)=> {
    inp.forEach((e,i)=> op[i] = op[i] ? op[i]+e : e)
    return op
},[])

console.log(op)

Answer 9

Answer №5

To efficiently sum up the values from multiple arrays, you can utilize .reduce with a for...of loop to extract the index and value of each inner array by utilizing the entries method. Then, simply assign them based on their indexes to an accumulator Array and calculate their sum.

let totalSum = list.reduce((acc, arr) => {
 for(let [index, num] of arr.entries()) acc[index] = (acc[index] || 0) + num;
 return acc;
}, []);

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1]
]

let totalSum = list.reduce((acc, arr) => {
 for(let [index, num] of arr.entries()) acc[index] = (acc[index] || 0) + num;
 return acc;
}, []);

console.log(totalSum);

Answer 10

To efficiently sum up the values from multiple arrays, you can utilize .reduce with a for...of loop to extract the index and value of each inner array by utilizing the entries method. Then, simply assign them based on their indexes to an accumulator Array and calculate their sum.

let totalSum = list.reduce((acc, arr) => {
 for(let [index, num] of arr.entries()) acc[index] = (acc[index] || 0) + num;
 return acc;
}, []);

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1]
]

let totalSum = list.reduce((acc, arr) => {
 for(let [index, num] of arr.entries()) acc[index] = (acc[index] || 0) + num;
 return acc;
}, []);

console.log(totalSum);

Answer 11

Answer №6

Implement a solution using nested loops:

const blocklist = [[2,9,1,2], [2,3,9,4], [4,7,8,1]], calculatedBlocks = [];
for (let j = 0, sum = 0; j < blocklist[0].length; j++, sum = 0) {
  for (let i = 0; i < blocklist.length; i++) sum += blocklist[i][j];
  calculatedBlocks.push(sum);
}

console.log(calculatedBlocks);

Answer 12

Implement a solution using nested loops:

const blocklist = [[2,9,1,2], [2,3,9,4], [4,7,8,1]], calculatedBlocks = [];
for (let j = 0, sum = 0; j < blocklist[0].length; j++, sum = 0) {
  for (let i = 0; i < blocklist.length; i++) sum += blocklist[i][j];
  calculatedBlocks.push(sum);
}

console.log(calculatedBlocks);

What is the process for finding the total of numerous arrays?

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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