Group By Index

gistfile1.txt

using System;
using System.Linq;	
using System.Collections.Generic;

public class Program
{
	public static void Main()
	{
		var s = new List<int> { 1,2,3,34,5,678,8,5,4,5,7,8,7,4,3,3,6,8,4};
		var groups =  s.Select((value,index)=>new { Value= value,Index=index}).GroupBy(i=>i.Index/2,v=>v.Value);
 		var x = groups.ToList();
		
		foreach (var t in x){
			var xx = t.ToList();
			Console.WriteLine(xx.Count != 2 ? "ONE element " + xx.First() : "TWO elements " + xx.First() + " " + xx.Last());
		}
		Console.WriteLine("Hello World");
	}
}