OrderBy and GroupBy in LINQ

If you are familiar with SQL,You would know it can enable you to perform some relational operations like the data to be returned in a specific Order and get the summary values based on the rows in each group.Here the LINQ is provide the same functionality
OrderBy:
The OrderBy is used to retrieve the data in particular order.The OrderBY expects a method as its argument.This methods identifies expressions that you want to use to sort the data.
For this i will show an example to get names of each city in AllCountry array

IEnumerable citynames=Allcountry.OrderBy(acoun=>acoun.CityName).Select(City=>city.CityName)
List li=New List();
 foreach(string name in Country)
  {
         li.add(name);
  }
 foreach (string s in list) // Loop through List with foreach
  {
 Console.WriteLine(s);
  }

The OrderByDescending is get the data in descending order.Here there one method i.e ThenByDescending which is used for more than one key value
GroupBy:
The GroupBy method is used to group the data to common values in one or more Fields.The GroupBy method expects a methods that specify the fields to group the data

var citiesGroupByCountry= Allcountry.GroupBy(acoun=>acoun.Country);
foreach(var citiesPerCountry in citiesGroupByCountry)
{
 foreach(var citis in citiesPerCountry)
 {
   Console.Writeline(Country.CountyName);
 }
}