how to split array into given number in javascript

Question

I have an array and i have to split it into given number and last splited array should accommodate remaining elements if (remaining array size < given_no/2)

for example

var arr = [1,2,3,4,5,6,7,8,9,10,11]

if given_no 2 = Math.round(arr.length/2)= chunk_size 6 = [[1,2,3,4,5,6],[6,7,8,9,10]] 
if given_no 3 = Math.round(arr.length/3)= chunk_size 4 = [[1,2,3,4],[5,6,7,8],[9,10,11]]
if given_no 4 = Math.round(arr.length/4)= chunk_size 3 = [[1,2,3],[4,5,6],[7,8,9],[10,11]]

Math.round(11/2) == 6, not 5. Did you mean Math.floor(11/2)? - If so, Math.floor(11/3) == 3 and Math.floor(11/4) == 2... Also, I'm unclear about "if (remaining array size < given_no/2)". — iAmOren
– iAmOren, Commented Jul 16, 2020 at 7:15

Vivek Jain · Accepted Answer · 2020-07-16 09:27:14Z

2

First of all Math.round(arr.length/2) will return 6 not 5. Please see below code. I have created splitArr function which will return split array based on given number.

var arr = [1,2,3,4,5,6,7,8,9,10,11];
console.log('Given 2: ' + JSON.stringify(splitArr(arr, 2))); // given 2
console.log('Given 3: ' + JSON.stringify(splitArr(arr, 3))); // given 3
console.log('Given 4: ' + JSON.stringify(splitArr(arr, 4))); // given 4
console.log('Given 5: ' + JSON.stringify(splitArr(arr, 5))); // given 5
console.log('Given 6: ' + JSON.stringify(splitArr(arr, 6))); // given 6

    function splitArr(arr, given) {
      var arrSize = arr.length
      var split = Math.round(arrSize/given);
      var returnArr = [];
      var loopCount;
      for(i = 0; i < given; i++){
        loopCount = (i*split)+split;
        loopCount = loopCount > arrSize ? arrSize : loopCount;
        
        var innerArr = arr.slice((i*split), loopCount)

        returnArr.push(innerArr);
      }

      if(loopCount < arr.length){
         innerArr.push(...arr.slice(loopCount, arrSize));
      }
      
      return returnArr;
    }

edited Jul 16, 2020 at 9:27

answered Jul 16, 2020 at 6:59

Vivek Jain

2,8726 gold badges14 silver badges29 bronze badges

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

6 Comments

NRaj Over a year ago

It fails for => splitArr(5); // given 5 => Given 5: [[1,2],[3,4],[5,6],[7,8],[9,10]]...where is element '11'

Vivek Jain Over a year ago

@NRaj please verify edited answer and upvote if it works.

NRaj Over a year ago

How about performance , If array size in beween 100k to 500k?

Vivek Jain Over a year ago

Improved my answer please verify that. Removed 2 inner for loops this will improve performance.

Rahul Bhobe Over a year ago

For give = 5, you seem to have the further nesting: Given 5: [[1,2],[3,4],[5,6],[7,8],[9,10,[11]]]. You have [9, 10, [11]]

|

Rahul Bhobe · Accepted Answer · 2020-07-16 08:08:14Z

1

You can use Math.round() and array.slice().

var splitArray = (arr, num) => {
    let result = [];
    let size   = Math.round(arr.length/num); 
    for (let i=0; i<num; i++) {
        let end = i === num-1 ? arr.length : (i+1) * size;
        result.push(arr.slice(i*size, end));
    }
    return result;  
} 

var arr = [1,2,3,4,5,6,7,8,9,10,11];
console.log(JSON.stringify(splitArray(arr, 2)));
console.log(JSON.stringify(splitArray(arr, 3)));
console.log(JSON.stringify(splitArray(arr, 4)));
console.log(JSON.stringify(splitArray(arr, 5)));

edited Jul 16, 2020 at 8:08

answered Jul 16, 2020 at 6:59

Rahul Bhobe

4,4714 gold badges19 silver badges35 bronze badges

3 Comments

Vivek Jain Over a year ago

this is not working with console.log(JSON.stringify(splitArray(arr, 5)));

NRaj Over a year ago

Yes, this also fails for console.log(JSON.stringify(splitArray(arr, 5)));

Rahul Bhobe Over a year ago

OK Math.round() it is. Fixed.

Gopi krishna · Accepted Answer · 2020-07-16 06:42:45Z

0

 function splitintochunks(arr,l){
    let result=[];
    while(arr.length>0){
    result.push(arr.splice(0,l));
    }
    return result;
}
//EXAMPLE: call in the below way spltIntoChunks([1,2,3,4,5,6,7,8,9,10,11],5);

answered Jul 16, 2020 at 6:42

Gopi krishna

3551 silver badge13 bronze badges

2 Comments

Siju Samson Over a year ago

This will not work, please test it once, and then give appropriate result.

Gopi krishna Over a year ago

@SijuSamson, got my mistake , thanks :) for adding the comment

Collectives™ on Stack Overflow

how to split array into given number in javascript

3 Answers 3

6 Comments

3 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

6 Comments

3 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related