ReactJS: Help debugging? Sum of each array NOT columns

user_14773371 0
Viewed 95

Need help with figuring out how to get the sum of multiple arrays.

This is my Data outputting from the console.log:

(4) [empty, Array(1), Array(1), Array(4)]
1: [50, 30]
2: [100, 100, 50]
3: (4) [500, 10, 50, 300]

Expected output:

1: [80] 
2: [250] 
3: [860]

Methods used:

  1. This code below doesn't work, it's just the columns of each row

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

code source : How to calculate the sum of multiple arrays?

  1. This code gives me a weird string:

     const savingsTotal = saveID.reduce((sum, value) =>  sum += value, 0)

Output: 050100500,10,50,300

  1. Thought if I list with a key that would work, eg [saved: 500], but it didn't up working either.

     const savingsTotal = saveID.map(({saved}) => saved.reduce((sum, value) => sum += value, 0))

Output: breaks code, can't find [saved : 500] due to the previous function which is:

  if (save.length > 0 ) { 
  const saveID = save.reduce((savedAmount, { goal_id, saved }) => {
    (savedAmount[goal_id] = savedAmount[goal_id] || []).push({"saved": saved});
    return savedAmount;
  }, []); ****Changed the .push so I would be able to add a key, normally it's without.

code source: How to get a the sum of multiple arrays within an array of objects?

Can someone help me out with the logic?

reactjs arrays javascript
3 Answers

Map through the original array of arrays. then use reduce to get the respective sum of their parts:

const ar = [[50, 30], [100, 100, 50], [500, 10, 50, 300]];
const sum_array = ar.map(item => item.reduce((acc, val) => acc + val, 0))
console.log(sum_array)

user_19279910

You can loop over the outer array and use reduce to find the sum of each constituent array.

const arr = [, [50, 30],[100, 100, 50], [500, 10, 50, 300]];
for(let i = 0; i < arr.length; i++){
  if(Array.isArray(arr[i])){
    console.log(i + ': ' + arr[i].reduce((acc,curr)=>acc+curr, 0));
  }
}

If you want to produce a result array instead of just printing it, you can use map.

const arr = [, [50, 30],[100, 100, 50], [500, 10, 50, 300]];
const res = arr.map(x => x.reduce((acc,curr)=>acc+curr, 0));
console.log(res);

user_95131840

Try this:

let arr = [10, 70],
    arr2 = [100, 100, 50],
    arr3 = [500, 10, 50, 300]

console.log(arr.reduce((sum, carry) => sum + carry));
console.log(arr2.reduce((sum, carry) => sum + carry));
console.log(arr3.reduce((sum, carry) => sum + carry));

user_61158550
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