List(Of T).Reverse Method (Int32, Int32)

 
System_CAPS_noteNote

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Reverses the order of the elements in the specified range.

Namespace:   System.Collections.Generic
Assembly:  mscorlib (in mscorlib.dll)

Public Sub Reverse (
	index As Integer,
	count As Integer
)

Parameters

index
Type: System.Int32

The zero-based starting index of the range to reverse.

count
Type: System.Int32

The number of elements in the range to reverse.

Exception Condition
ArgumentOutOfRangeException

index is less than 0.

-or-

count is less than 0.

ArgumentException

index and count do not denote a valid range of elements in the List(Of T).

This method uses Array.Reverse to reverse the order of the elements.

This method is an O(n) operation, where n is Count.

The following example demonstrates both overloads of the Reverse method. The example creates a List(Of T) of strings and adds six strings. The Reverse() method overload is used to reverse the list, and then the Reverse(Int32, Int32) method overload is used to reverse the middle of the list, beginning with element 1 and encompassing four elements.

Imports System
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Parasauralophus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Coelophysis")
        dinosaurs.Add("Oviraptor")

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        dinosaurs.Reverse()

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        dinosaurs.Reverse(1, 4)

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

    End Sub
End Class

' This code example produces the following output:
'
'Pachycephalosaurus
'Parasauralophus
'Mamenchisaurus
'Amargasaurus
'Coelophysis
'Oviraptor
'
'Oviraptor
'Coelophysis
'Amargasaurus
'Mamenchisaurus
'Parasauralophus
'Pachycephalosaurus
'
'Oviraptor
'Parasauralophus
'Mamenchisaurus
'Amargasaurus
'Coelophysis
'Pachycephalosaurus

Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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