using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var people = new[]

                {

                    new { Name = "Vernon", Gender = "Male", CountryCode = "GB" },

                    new { Name = "Carrie", Gender = "Female", CountryCode = "CA" },

                    new { Name = "Joanna", Gender = "Female", CountryCode = "US" },

                    new { Name = "Thomas", Gender = "Male", CountryCode = "ES" },

                    new { Name = "James", Gender = "Male", CountryCode = "GB" },

                    new { Name = "Elly", Gender = "Female", CountryCode = "US" }

                };

        var countries = new[]

                        {

                                new {CountryName = "United Kingdom", Code = "GB"},

                                new {CountryName = "United States", Code = "US"},

                                new {CountryName = "Canada", Code = "CA"},

                                new {CountryName = "France", Code = "FR"},

                                new {CountryName = "Spain", Code = "ES"}

                        };

​

​

        var results = countries.GroupJoin(people,

                                          arg => arg.Code,

                                          arg => arg.CountryCode,

                                          (c, p) => new {Country = c, People = p})

                                .SelectMany(arg => arg.People.DefaultIfEmpty(),

                                                   (c, p) => new {c.Country, People = p});

​

        foreach (var g in results)

        {

            Console.WriteLine("{0} - {1}", g.Country.CountryName, g.People == null ? "NULL" : g.People.Name);

        }

    }

}