Linq - Group join sample

public void LinqSample()
{
    string[] categories = new string[]{ 
        "Beverages", 
        "Condiments", 
        "Vegetables", 
        "Dairy Products", 
        "Seafood" };
 
    List<Product> products = GetProductList();
 
    var q =
        from c in categories
        join p in products on c equals p.Category into ps
        select new { Category = c, Products = ps };
 
    foreach (var v in q)
    {
        Console.WriteLine(v.Category + ":");
        foreach (var p in v.Products)
        {
            Console.WriteLine("   " + p.ProductName);
        }
    }
}