Linq101-Element

 using System;
 using System.Collections.Generic;
 using System.Linq;

 namespace Linq101
 {
     class Element
     {
         /// <summary>
         /// This sample uses First to return the first matching element as a Product, instead of as a sequence containing a Product.
         /// </summary>
         public void Linq58()
         {
             List<Data.Product> products = Data.GetProductList();

             Data.Product product12 = (from p in products
                                       where p.ProductID ==
                                       select p).First();

             ObjectDumper.Write(product12);
         }

         /// <summary>
         /// This sample uses First to find the first element in the array that starts with 'o'.
         /// </summary>
         public void Linq59()
         {
             string[] strings = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };

             string startsWithO = strings.First(s => s[] == 'o');

             Console.WriteLine("A string starting with 'o': {0}", startsWithO);
         }

         /// <summary>
         /// This sample uses FirstOrDefault to try to return the first element of the sequence, unless there are no elements, in which case the default value for that type is returned.
         /// </summary>
         public void Linq60()
         {
             int[] numbers = { };

             int firstNumOrDefault = numbers.FirstOrDefault();

             Console.WriteLine(firstNumOrDefault);
         }

         /// <summary>
         /// This sample uses FirstOrDefault to return the first product whose ProductID is 789 as a single Product object, unless there is no match, in which case null is returned.
         /// </summary>
         public void Linq61()
         {
             List<Data.Product> products = Data.GetProductList();

             Data.Product product789 = products.FirstOrDefault(p => p.ProductID == );

             Console.WriteLine("Product 789 exists: {0}", product789 != null);
         }

         /// <summary>
         /// This sample uses ElementAt to retrieve the second number greater than 5 from an array.
         /// </summary>
         public void Linq62()
         {
             int[] numbers = { , , , , , , , , ,  };

             int number = (from n in numbers
                           where n >
                           select n).ElementAt();

             Console.WriteLine("Second number > 5: {0}", number);
         }
     }
 }