using System;

using System.Collections.Generic;

public class Program

{

    public static IEnumerable<IEnumerable<int>> batchesOfTwo(int total, int[] data){

        int batchSize = 2;

        var batch = new List<int>();

        for (int i = 0; i < data.Length; i++)

        { 

            batch.Add(data[i]);

            if(batch.Count == batchSize || i == data.Length - 1) 

            {

                yield return batch;

                batch = new List<int>();

            }

        }

    }

    public static void Main()

    {

        int[] data = {1,1,2,2,3,3,4,4,5,5};

        int total = 0;

        IEnumerable<IEnumerable<int>> batched = batchesOfTwo(total, data);

        foreach(var batch in batched){

            // Log out items in batches

            Console.Write("batch:");

            foreach(var item in batch){

            Console.Write(item);

            }

            Console.WriteLine("");

        }

    }

}

​

​