Csharp/C Sharp/LINQ/DefaultIfEmpty

DefaultIfEmpty Demo

 
using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
    public static void Main() {
        string[] presidents = {"G", "H", "a", "H", "over", "Jack"};
        string name =
          presidents.Where(n => n.Equals("H")).DefaultIfEmpty("Missing").First(); Console.WriteLine(name);
    }
}

Using DefaultIfEmpty in Where clause

 
using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
    public static void Main() {
        string[] presidents = {"G", "H", "a", "H", "over", "Jack"};
        string jones = presidents.Where(n => n.Equals("H")).DefaultIfEmpty().First();
        if (jones != null)
            Console.WriteLine("H was found.");
        else
            Console.WriteLine("H was not found.");
    }
}

Without Using DefaultIfEmpty

 
using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
    public static void Main() {
        string[] presidents = {"G", "H", "a", "H", "over", "Jack"};
        string jones = presidents.Where(n => n.Equals("H")).First();
        if (jones != null)
            Console.WriteLine("H was found");
        else
            Console.WriteLine("H was not found");
    }
}