Enumerable.Any<TSource> Method (IEnumerable<TSource>)

Type Parameters

• TSource
  The type of the elements of source.

Parameters

• source
  Type: System.Collections.Generic.IEnumerable<TSource>
  The IEnumerable<T> to check for emptiness.

Return Value

Type: System.Boolean
true if the source sequence contains any elements; otherwise, false.

      ' Create a list of Integers.
      Dim numbers As New List(Of Integer)(New Integer() {1, 2})

      ' Determine if the list contains any items.
      Dim hasElements As Boolean = numbers.Any()

      ' Display the output.
      Dim text As String = IIf(hasElements, "not ", "")
      outputBlock.Text += "The list is " & text & "empty." & vbCrLf

      ' This code produces the following output:
      '
      ' The list is not empty.

         List<int> numbers = new List<int> { 1, 2 };
         bool hasElements = numbers.Any();

         outputBlock.Text += String.Format("The list {0} empty.",
             hasElements ? "is not" : "is") + "\n";

         // This code produces the following output:
         //
         // The list is not empty. 

Structure Pet
   Public Name As String
   Public Age As Integer
End Structure

Structure Person
   Public LastName As String
   Public Pets() As Pet
End Structure

Sub AnyEx2()
   Dim people As New List(Of Person)(New Person() _
       {New Person With {.LastName = "Haas", _
                         .Pets = New Pet() {New Pet With {.Name = "Barley", .Age = 10}, _
                                            New Pet With {.Name = "Boots", .Age = 14}, _
                                            New Pet With {.Name = "Whiskers", .Age = 6}}}, _
         New Person With {.LastName = "Fakhouri", _
                          .Pets = New Pet() {New Pet With {.Name = "Snowball", .Age = 1}}}, _
         New Person With {.LastName = "Antebi", _
                          .Pets = New Pet() {}}, _
         New Person With {.LastName = "Philips", _
                          .Pets = New Pet() {New Pet With {.Name = "Sweetie", .Age = 2}, _
                                             New Pet With {.Name = "Rover", .Age = 13}}}})

   ' Determine which people have a non-empty Pet array.
   Dim names = From person In people _
               Where person.Pets.Any() _
               Select person.LastName

   For Each name As String In names
      outputBlock.Text &= name & vbCrLf
   Next

   ' This code produces the following output:
   '
   ' Haas
   ' Fakhouri
   ' Philips

End Sub

class Pet
{
   public string Name { get; set; }
   public int Age { get; set; }
}
class Person
{
   public string LastName { get; set; }
   public Pet[] Pets { get; set; }
}

public static void AnyEx2()
{
   List<Person> people = new List<Person>
           { new Person { LastName = "Haas",
                          Pets = new Pet[] { new Pet { Name="Barley", Age=10 },
                                             new Pet { Name="Boots", Age=14 },
                                             new Pet { Name="Whiskers", Age=6 }}},
             new Person { LastName = "Fakhouri",
                          Pets = new Pet[] { new Pet { Name = "Snowball", Age = 1}}},
             new Person { LastName = "Antebi",
                          Pets = new Pet[] { }},
             new Person { LastName = "Philips",
                          Pets = new Pet[] { new Pet { Name = "Sweetie", Age = 2},
                                             new Pet { Name = "Rover", Age = 13}} }
           };

   // Determine which people have a non-empty Pet array.
   IEnumerable<string> names = from person in people
                               where person.Pets.Any()
                               select person.LastName;

   foreach (string name in names)
   {
      outputBlock.Text += name + "\n";
   }

   /* This code produces the following output:

      Haas
      Fakhouri
      Philips
   */
}