Sorting using two arrays

Question

There are two arrays: The first one contain numbers, and the second one contains "weight" of the first array values.

It works like this:

arr1 = [56,65,100,89,180,90];

"Weight" of the numbers are calculated in this way:

 56 = 5+6 = 11;
 65 = 6+5 = 11;
 100 = 1+0+0 = 1; and so on..

So, arr2 = [11,11,1,17,9,9];

My question is how can I sort the values of the arr1 according to values of arr2?

I tried to modify simple bubble sort for this problem, but nothing changed.

function bubble(arr1, arr2) {
  var len = arr1.length;
  for (var i = 0; i < len; i++) {
    for (var j = 0; j < len - i - 1; j++) {
      if (arr2[j] > arr2[j + 1]) {
        var temp = arr1[j];
        arr1[j] = arr1[j + 1];
        arr1[j + 1] = temp;
      }
    }
  }
  return arr1;
}

arr1 = [56, 65, 100, 89, 180, 90];

arr2 = [11, 11, 1, 17, 9, 9];

console.log(bubble(arr1, arr2));

I expect the output of the bubble function to be [100,180,90,56,65,89]. This is why:

FirstArray -          [56,65,100,89,180,90] - arr1
"Weight of the values"[11,11, 1, 17, 9, 9 ] - arr2
Output                [100,180,90,56,65,89]
                      [1,  9,  9 ,11,11,17]

Possible duplicate of Javascript - sort array based on another array — Prune
– Prune, Commented Aug 21, 2019 at 21:29
You have to sort both arrays, not just one. Otherwise the arrays start to missmatch and you get chaos — Jonas Wilms
– Jonas Wilms, Commented Aug 21, 2019 at 21:36
@JonasWilms if second array is derived from first , then sorting arr1 alone works - codepen.io/nagasai/pen/WNeoaEv?editors=1010 — Naga Sai A
– Naga Sai A, Commented Aug 21, 2019 at 21:42
Why not just supply a comparison function and compute the "weight" during the sort? — Jim Mischel
– Jim Mischel, Commented Aug 21, 2019 at 21:43

Paul · Accepted Answer · 2019-08-21 21:43:22Z

2

You can just calculate the weight on the fly while sorting:

const arr = [56,65,100,89,180,90];

arr.sort( (a,b) => 
  (a + '').split( '' ).reduce( (sum,x) => sum + +x, 0 ) -
  (b + '').split( '' ).reduce( (sum,x) => sum + +x, 0 )
);

console.log( arr );

answered Aug 21, 2019 at 21:43

Paul

142k28 gold badges285 silver badges272 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Naga Sai A · Accepted Answer · 2019-08-21 21:44:36Z

0

To achieve expected result, use below option of sorrting arr1 with logic mentioned in question

Sort arr1 bycomparing sum of digits
Convert number to string and split it to array
Use reduce sum all the digits and compare with the array elements

var arr1 = [56, 65, 100, 89, 180, 90];
var arr2 = [11, 11, 1, 17, 9, 9];

console.log(
  arr1.sort(
    (a, b) =>
      a
        .toString()
        .split("")
        .reduce((acc, v) => parseInt(acc) + parseInt(v)) -
      b
        .toString()
        .split("")
        .reduce((acc, v) => parseInt(acc) + parseInt(v))
  )
);

codepen - https://codepen.io/nagasai/pen/WNeoaEv?editors=1010

answered Aug 21, 2019 at 21:44

Naga Sai A

11k1 gold badge24 silver badges41 bronze badges

1 Comment

Никита Ковалёв Over a year ago

My thanks! I just feel a little bit weak in arrow functions, so I need more practice.

Collectives™ on Stack Overflow

Sorting using two arrays

2 Answers 2

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related