how to compare sum of two values in array in NodeJs?

Question

Basically I have two arrays. They are sorted. I have managed to compare them with efficiency. Now I require to find the sum of two values of arrays and compare them. For example

arr1 = [5,8,10] // sum of first two is 13
arr2 = [6,7,12] // sum of first two is also 13

if that happens, do something. I can't think of a way to do that. Any help will highly be appreciated.

do you always need to compare first two elements of arrays?? Are both arrays always non empty with atleast two elements? — Navjot Singh, Jun 14 '19 at 14:26
`arr1.slice(0,2).reduce((sum,item) => sum+=item) == arr2.slice(0,2).reduce((sum,item) => sum+=item)` — Yevhen Horbunkov, Jun 14 '19 at 14:27
yes I need to compare first two elements. And yes both arrays will always be non-empty — M Safdar Ali Khan, Jun 14 '19 at 14:28
@U25lYWt5IEJhc3RhcmQg why are you using such heavy functions like slice when it is simple if statement. — Navjot Singh, Jun 14 '19 at 14:28
@NavjotSingh : I'm assuming, it's not just sum of the first two items in the real example, so my code can be easily scaled — Yevhen Horbunkov, Jun 14 '19 at 14:30
@U25lYWt5IEJhc3RhcmQg Aha...you sure? you just used 2 as a value in your slice function which makes an assumption that you are going for first two elements. — Navjot Singh, Jun 14 '19 at 14:31
@NavjotSingh : have array of 1k items and need to sum up 500 of these, would that be easier to type those manually or swap '2' for '500'? — Yevhen Horbunkov, Jun 14 '19 at 14:32
@NavjotSingh : Well, I can't beat that - establishing telepathic connection is none of my skills — Yevhen Horbunkov, Jun 14 '19 at 14:34

score -1 · Accepted Answer · answered Jun 14 '19 at 14:27

-1

If only value from first 2 index is what you required , then you can get the index and do the summation

let arr1 = [5, 8, 10],
  arr2 = [6, 7, 12];

if (arr1[0] + arr1[1] === arr2[0] + arr2[1]) {
  console.log(true)

}

answered Jun 14 '19 at 14:27

brk

48,835
10
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thank you. this will solve my problem. – M Safdar Ali Khan Jun 14 '19 at 14:34
@MSafdarAliKhan Thanks , happy to help – brk Jun 14 '19 at 14:40

score -1 · Answer 2 · answered Jun 14 '19 at 14:29

-1

try using reduce on the two array with your own rule

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce How to find the sum of an array of numbers

answered Jun 14 '19 at 14:29

Phoenix5650

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11

how to compare sum of two values in array in NodeJs?

2 Answers2