Processing a C# Dictionary using LINQ

Question

How do I write the "// Display using Foreach" loop implementation using LINQ Lambda Expression / Statemene Expression?

I want to simplify my development and avoid nested foreach loops as much as possible. I am trying to include more logic with in the second foreach statement and I want to use Lambda / Statement expression.

 internal class Program
{
    internal class Country
    {
        public string CountryName { get; set; }
        public int CountryCode { get; set; }
    }
    static void Main(string[] args)
    {
        List<Country> countries = new List<Country>()
        {
            new Country{CountryName = "India", CountryCode=1},
            new Country{CountryName = "Andaman Nicobar", CountryCode=1},
            new Country{CountryName = "United States of America",  CountryCode=2},
            new Country{CountryName = "Alaska",  CountryCode=2},
            new Country{CountryName = "Hawaii",  CountryCode=2},
            new Country{CountryName = "United Kingdom", CountryCode=3},
            new Country{CountryName = "Australia", CountryCode=4}
        };

        Dictionary<int, List<Country>> countriesDictionary = new Dictionary<int, List<Country>>();
        foreach (Country country in countries)
        {
            if (!countriesDictionary.ContainsKey(country.CountryCode))
                countriesDictionary.Add(country.CountryCode, new List<Country>());
            countriesDictionary[country.CountryCode].Add(country);                
        }

       // Display using Foreach

        foreach (int key in countriesDictionary.Keys)
        {                             
            List<Country> dCountries = countriesDictionary[key];

            foreach (Country country in dCountries)
            {
                if (country.CountryCode.Equals(key))
                {
                    Console.WriteLine(country.CountryName);
                }                
            }
            Console.WriteLine();            
        }
        Console.ReadLine();
    }

Please suggest.

Answer 1

This is another alternative:

countriesDictionary.ToList().ForEach
(
    pair =>
    {
        pair.Value.ForEach(country => Console.WriteLine(country.CountryName));
        Console.WriteLine();
    }
);

---

Also, this one based on Romoku's Answer(the answer was removed):

var countriesDictionary = countries.ToLookup(x => x.CountryCode, x => x);

foreach(var countryGroup in countriesDictionary)
{
    foreach(var country in countryGroup)
    {
        Console.WriteLine(country.CountryName);
    }
    Console.WriteLine();
}

Answer 2

If you want to group countries by code, then you don't need two dictionaries. Use Enumerable.GroupBy

foreach(var codeGroup in countries.GroupBy(c => c.CountryCode))
{
    foreach(var country in codeGroup)
       Console.WriteLine(country.CountryName);

    Console.WriteLine();
}

Or just use your countriesDictionary (it already has countries grouped by code):

foreach(var kvp in countriesDictionary)
{
    foreach(var country in kvp.Value)
       Console.WriteLine(country.CountryName);

    Console.WriteLine();
}