CODEWITHSUNDEEP
javascriptjquery
Gopal
Gopal

Reputation: 217

Split array into chunks and sum each index, then merge into another array

I am splitting an array into two arrays arr1 & arr2. Then I want to sum the values and bind into another array like arr3. How can I do this?

var arr1 = [1,2,3,4]
var arr2 = [2,3,4,4]

var arr3 = [3,5,7,8]

this works fine with static arrays, but my problem is 

var TotalOfArray = [];
var temparray = [];

for (i = 0, j = x.length; i < j; i += chunk) {

        temparray = x.slice(i, i + chunk);

        if (temparray.length == chunk) {

            console.log("before loop: "+TotalOfArray.length);

            if (TotalOfArray.length == 0) {

                for (i in temparray) {
                    TotalOfArray[i] = temparray[i];
                }

                console.log("after loop: "+TotalOfArray.length);

            } else {

                for (i in temparray) {
                    TotalOfArray[i] = TotalOfArray[i] + temparray[i];
                }

            }

        }

    }

As you can see, x will be the main array which I am splicing into a temparray array, so every time it will splice with array length 31 and than I want to do sum, chunk = 31 as of now. But it's not going into ELSE part.

Upvotes: 0

Views: 477

Answers (4)

GibboK
GibboK

Reputation: 73918

If two arrays have equal length you can can use Array.prototype.map();

var data1 = [1,2,3,4],
    data2 = [2,3,4,4],
    result;
result = data1.map(function(value, i){
    return value + data2[i];
});
console.log(result);

Upvotes: 1

KevBot
KevBot

Reputation: 18898

Equal Length Arrays:

This is just a more simple version, that assumes equal lengths from both arrays. For a solution that works with variable length arrays, read further on.

var arr1 = [1, 2, 3, 4];
var arr2 = [2, 3, 4, 4];

var arr3 = arr1.map(function(a, i) {
  return a + arr2[i];
});

console.log(arr3);

Variable Length Arrays:

This is going to be a more robust solution regardless. But it finds the array with the most values in it, and uses that for the map. Then, if undefined values are found in the other array, it will use 0 as the other number.

var arr1 = [1, 2, 3, 4];
var arr2 = [2, 3, 4, 4, 5];

var sorted = [arr1, arr2].sort((a, b) => b.length - a.length);

var arr3 = sorted[0].map(function(a, i) {
  return a + (sorted[1][i] || 0);
});

console.log(arr3);

Upvotes: 4

flott
flott

Reputation: 231

var arr1 = [1,2,3,4]
var arr2 = [2,3,4,4]
var arr3 = []

for (var i = 0; i < arr1.length; i++) {
    arr3.push(arr1[i] + arr2[i])
}

Assuming arr1 and arr2 have the same length.

Upvotes: 0

Krzysztof Krasoń
Krzysztof Krasoń

Reputation: 27476

Use for loop:

    var arr1 = [1,2,3,4]
    var arr2 = [2,3,4,4]
    var arr3 = []
    for (i in arr1) { arr3[i] = arr1[i] + arr2[i]; }

    console.log(arr3)

Upvotes: 1

Related Questions