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
{
		/// &lt;summary&gt;
		/// Slices the specified collection like Python does
		/// &lt;/summary&gt;
		/// &lt;typeparam name="T"&gt;&lt;/typeparam&gt;
		/// &lt;param name="me"&gt;the collection&lt;/param&gt;
		/// &lt;param name="start"&gt;The start point.&lt;/param&gt;
		/// &lt;param name="end"&gt;The end point.&lt;/param&gt;
		/// &lt;returns&gt;&lt;/returns&gt;
		/// &lt;example&gt;&lt;code&gt;
		/// 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,&lt;/code&gt;&lt;/example&gt;
		/// &lt;exception cref="System.ArgumentException"&gt;starting point must be less than or equal to ending point;start&lt;/exception&gt;
		public static IEnumerable&lt;T&gt; Slice&lt;T&gt;(this IEnumerable&lt;T&gt; me, int? start = null, int? end = null)
		{
			if (start.HasValue &amp;&amp; end.HasValue &amp;&amp; start.Value &gt; end.Value)
			{
				throw new ArgumentException("starting point must be less than or equal to ending point", "start");
			}

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

			if (end.HasValue &amp;&amp; end &lt; 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
{
        /// &lt;summary&gt;
        /// Slices the specified collection like Python does
        /// &lt;/summary&gt;

Cached Result

/app/:::::::