C# Online Compiler | .NET Fiddle

using System;
using System.Collections.Generic;
using System.Linq;
					
public class Program
{
	public static void Main()
	{
		var numbers=new[]{1,2,3,4,5};
		var eg = numbers.Slice(-3,-1);
		foreach (var i in eg)
		{
			Console.Write("{0}, ", i);
		}
		Console.WriteLine();	// Output: 3, 4,

	}
}

public static class Extensions
{
		/// <summary>
		/// Slices the specified collection like Python does
		/// </summary>
		/// <typeparam name="T"></typeparam>
		/// <param name="me">the collection</param>
		/// <param name="start">The start point.</param>
		/// <param name="end">The end point.</param>
		/// <returns></returns>
		/// <example><code>
		/// var numbers=new[]{1,2,3,4,5};
		/// var eg = numbers.Slice(-3,-1);
		/// foreach (var i in eg)
		///	{
		///		Console.Write("{0}, ", i);
		///	}
		///	Console.Writeline();	// Output: 3, 4,</code></example>
		/// <exception cref="System.ArgumentException">starting point must be less than or equal to ending point;start</exception>
		public static IEnumerable<T> Slice<T>(this IEnumerable<T> me, int? start = null, int? end = null)
		{
			if (start.HasValue && end.HasValue && start.Value > end.Value)
			{
				throw new ArgumentException("starting point must be less than or equal to ending point", "start");
			}

			if (start.HasValue && start < 0)
			{
				start = me.Count() + start;
			}

			if (end.HasValue && end < 0)
			{
				end = me.Count() + end;
			}

			if (!start.HasValue)
			{
				start = 0;
			}

			if (!end.HasValue)
			{
				end = me.Count();
			}

			return me.Skip(start.Value).Take(end.Value - start.Value);
		}
	
}

 
using System;
using System.Collections.Generic;
using System.Linq;
                    
public class Program
{
    public static void Main()
    {
        var numbers=new[]{1,2,3,4,5};
        var eg = numbers.Slice(-3,-1);
        foreach (var i in eg)
        {
            Console.Write("{0}, ", i);
        }
        Console.WriteLine();    // Output: 3, 4,
​
    }
}
​
public static class Extensions
{
        /// <summary>
        /// Slices the specified collection like Python does
        /// </summary>

Cached Result

3, 4,