using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        //obtain a list of pets

        IEnumerable<Pet> pets = CreateListOfPets(); 

        //pass the pets list into our GetDogs method and yield return the first 2 dogs we find.

        foreach (var dog in  GetDogsUsingYield(pets).Take(2))

        {

            Console.WriteLine("- retrieved: " + dog.Name + " the " + dog.Animal);

        }

    }

​

    public static IEnumerable<Pet> GetDogsUsingYield(IEnumerable<Pet> pets){

        foreach (var pet in pets)

        {

            Console.WriteLine("Processing with yield: " + pet.Animal);

            if(pet.Animal=="Dog")

            {

                Console.WriteLine("yielding: " + pet.Animal);

                yield return pet;

            }

        }

    }

public static IEnumerable<Pet> CreateListOfPets(){

    return new List<Pet>{

        new Pet{Animal="Dog",Colour="Black", Name="Rocky"},

        new Pet{Animal="Cat",Colour="Black", Name="Betty"},

        new Pet{Animal="Dog",Colour="White", Name="Fluffy"},

        new Pet{Animal="Elephant",Colour="Grey", Name="Nellie"},

        new Pet{Animal="Dog",Colour="Brown", Name="Lassie"},

        new Pet{Animal="Cat",Colour="Brown", Name="Mr Jinx"},

        new Pet{Animal="Mouse",Colour="Brown", Name="Micky"},

        new Pet{Animal="Cat",Colour="Black", Name="Tom"},

        new Pet{Animal="Turtle",Colour="Green", Name="Leonardo"},

        new Pet{Animal="Yoda",Colour="Brown", Name="Lizard"}

    };

    }   

}

​

​

public class Pet{

    public string Animal {get;set;}

    public string Colour {get;set;}

    public string Name {get;set;}

}