Group an array to form three arrays based on the index

Question

I want to sort an array in a way that it gives back three arrays. So

var myArray = [\'1\',\'2\',\'3\',\'1\',\'2\',\'3\',\'1\',\'2\',\'3\',\'1\',\'2\',\'3\',\'1\'         


        

Answer 1

You could create a generic function which will group the array based on the n provided. Based on the result of index % n, push them into specific arrays. Here, n = 3. If you use i % 2, this will distribute the numbers into 2 arrays based on odd and even indices.

const myArray = ['1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3', '1', '2', '3'];

function group(array, n) {
  return myArray.reduce((acc, number, i) => {
    acc[i % n] = acc[i % n] || [];
    acc[i % n].push(number);
    return acc;
  }, [])
}

const grouped = group(myArray, 3);

console.log(JSON.stringify(grouped[0]))
console.log(JSON.stringify(grouped[1]))
console.log(JSON.stringify(grouped[2]))