Make an array of 60 items to an array of array with 20 items in each array

Question

I have an array of 60 items. I want to split it into an array within an array of 20 items in it.

Here are the codes that I have, but kind of stuck on how to separate into the array.

const initialData = get(certificate, "transcript", []);
const splitData = [];

This is how the splitTranscriptData should look like at the end

[[1,2,3...20],[21,22,23...40],[41,42,43...60]]

I am trying to make this a dynamic way of separating the initial array into 20 items in each array. For example, my initial array has 55 items, the end result will be 3 arrays with the last one having 15 items in it.

When there are more items in the initial array, let's say 70 items, it will split into 4 arrays with the last one having 10 items in it.

You can ```Array.prototype.slice``` function to create subarray from your array. — Tien Duong, Jul 22 '19 at 03:06
What if my initial array is like 55 items, and I still want it to split into 3 arrays just that the last one will have 15 items. — babo, Jul 22 '19 at 03:13
Am I right to say that I have to manually use ```Array.prototype.slice``` 3 times in my code to split my initial array? — babo, Jul 22 '19 at 03:17
No. You can use ```for``` loop with number of elements per subarray(20) to split your array to subarray. — Tien Duong, Jul 22 '19 at 03:21

helloitsjoe · Accepted Answer · 2019-07-22T03:34:35.900

You can use recursion to do this:

const split = (input, output = []) => {
  if (!input.length) return output;
  output.push(input.slice(0, 20))
  return split(input.slice(20), output)
}

const splitData = split(initialData);

Here's a JSFiddle of it working: https://jsfiddle.net/ma63cpbt/5/

This will dynamically split an array of any length into subarrays of length 20, with the last subarray holding any remaining items.

You could also pass in 20 as an argument if you want a different subarray length.

CoronaVirus · Answer 2 · 2019-07-22T03:45:39.940

0

var items = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];

var splittedData  = [];

function splitData(splitLength) {

    for(var i = 0;i<items.length; i+=splitLength) { 
        splittedData.push(items.slice(i,i+splitLength));        
    }

}

Call:

splitData(4);

Output:

edited Jul 22 '19 at 03:45

answered Jul 22 '19 at 03:40

CoronaVirus

401
2
7
20

Jee Mok · Answer 3 · 2019-07-22T04:08:53.190

0

You can split the array using lodash chunk:

_.chunk(initialData, 20);

edited Jul 22 '19 at 04:08

answered Jul 22 '19 at 03:51

Jee Mok

6,157
8
47
80

score 0 · Answer 4 · answered Jul 22 '19 at 06:18

0

No need to use any library u can easily do it heres the code :)

 const list = [1,2,3,...60]
    const arrayList = [
        list.slice(0,20),
        list.slice(20,40),
        list.slice(40,60),
    ]

answered Jul 22 '19 at 06:18

S M Hammad Shakil

79
1
5

score 0 · Answer 5 · answered Jul 22 '19 at 10:15

Array which needs to be splitted

var arr = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];

Function for splitting

size- size of the chunk. Here it should be 20

    const splittedArray = (arr, size) =>
      arr.length > size
        ? [arr.slice(0, size), ...splittedArray(arr.slice(size), size)]
        : [arr];

Calling the function with array and size of chunk as params

splittedArray(arr, 5)

score -1 · Answer 6 · answered Jul 22 '19 at 03:14

-1

If it's always going to be 1 x 60 array to a 3 x 20 array, you can hardcode the indices and do it like this:

splitData = [initialData.slice(0,20), initialData.slice(20,40), initialData.slice(40,60)]

answered Jul 22 '19 at 03:14

Katie Woolston

1
1
2

Make an array of 60 items to an array of array with 20 items in each array

6 Answers6

Array which needs to be splitted

Function for splitting

Calling the function with array and size of chunk as params