Groupby,cs

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

					
public class Program
{
	public static void Main()
	{
		// Student collection
		IList<Student> studentList = new List<Student>() { 
				new Student() { StudentID = 1, StudentName = "John", Age = 18 } ,
				new Student() { StudentID = 2, StudentName = "Steve",  Age = 21 } ,
				new Student() { StudentID = 3, StudentName = "Bill",  Age = 18 } ,
				new Student() { StudentID = 4, StudentName = "Ram" , Age = 20 } ,
				new Student() { StudentID = 5, StudentName = "Ron" , Age = 21 } 
			};
		
		var groupedResult = studentList.GroupBy(s => s.Age);

		foreach (var ageGroup in groupedResult)
		{
			Console.WriteLine("Age Group: {0}", ageGroup.Key);  //Each group has a key 
					 
			foreach(Student s in ageGroup)  //Each group has a inner collection  
				Console.WriteLine("Student Name: {0}", s.StudentName);
		}
		
	}
		
}

public class Student{

	public int StudentID { get; set; }
	public string StudentName { get; set; }
	public int Age { get; set; }
	
}