Articolo
11/18/2011

Array.Reverse Method (Array)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Reverses the sequence of the elements in the entire one-dimensional Array.

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

Syntax

'Declaration
Public Shared Sub Reverse ( _
    array As Array _
)

public static void Reverse(
    Array array
)

Parameters

array
Type: System.Array
The one-dimensional Array to reverse.

Exceptions

Exception	Condition
ArgumentNullException	array is nulla null reference (Nothing in Visual Basic).
RankException	array is multidimensional.

Remarks

After a call to this method, the element at myArray[i], where i is any index in the array, moves to myArray[j], where j equals (myArray.Length + myArray.GetLowerBound(0)) - (i - myArray.GetLowerBound(0)) - 1.

This method is an O(n) operation, where n is the Length of array.

Examples

The following code example shows how to reverse the sort of the values in an Array.

Note:
To run this example, see Building Examples That Use a Demo Method and a TextBlock Control.


Public Class Example

   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      ' Creates and initializes a new Array.
      Dim myArray As Array = Array.CreateInstance(GetType(String), 9)
      myArray.SetValue("The", 0)
      myArray.SetValue("quick", 1)
      myArray.SetValue("brown", 2)
      myArray.SetValue("fox", 3)
      myArray.SetValue("jumps", 4)
      myArray.SetValue("over", 5)
      myArray.SetValue("the", 6)
      myArray.SetValue("lazy", 7)
      myArray.SetValue("dog", 8)

      ' Displays the values of the Array.
      outputBlock.Text &= "The Array initially contains the " _
         + "following values:" & vbCrLf
      PrintIndexAndValues(outputBlock, myArray)

      ' Reverses the sort of the values of the Array.
      Array.Reverse(myArray)

      ' Displays the values of the Array.
      outputBlock.Text &= "After reversing:" & vbCrLf
      PrintIndexAndValues(outputBlock, myArray)
   End Sub 'Main



   Public Shared Sub PrintIndexAndValues(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal myArray As Array)
      Dim i As Integer
      For i = myArray.GetLowerBound(0) To myArray.GetUpperBound(0)
         outputBlock.Text &= String.Format(ControlChars.Tab + "[{0}]:" + ControlChars.Tab _
            + "{1}", i, myArray.GetValue(i)) & vbCrLf
      Next i
   End Sub
End Class

' This code produces the following output.
' 
' The Array initially contains the following values:
'     [0]:    The
'     [1]:    quick
'     [2]:    brown
'     [3]:    fox
'     [4]:    jumps
'     [5]:    over
'     [6]:    the
'     [7]:    lazy
'     [8]:    dog
' After reversing:
'     [0]:    dog
'     [1]:    lazy
'     [2]:    the
'     [3]:    over
'     [4]:    jumps
'     [5]:    fox
'     [6]:    brown
'     [7]:    quick
'     [8]:    The

using System;
public class Example
{

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {

      // Creates and initializes a new Array.
      Array myArray = Array.CreateInstance(typeof(String), 9);
      myArray.SetValue("The", 0);
      myArray.SetValue("quick", 1);
      myArray.SetValue("brown", 2);
      myArray.SetValue("fox", 3);
      myArray.SetValue("jumps", 4);
      myArray.SetValue("over", 5);
      myArray.SetValue("the", 6);
      myArray.SetValue("lazy", 7);
      myArray.SetValue("dog", 8);

      // Displays the values of the Array.
      outputBlock.Text += "The Array initially contains the following values:" + "\n";
      PrintIndexAndValues(outputBlock, myArray);

      // Reverses the sort of the values of the Array.
      Array.Reverse(myArray);

      // Displays the values of the Array.
      outputBlock.Text += "After reversing:" + "\n";
      PrintIndexAndValues(outputBlock, myArray);
   }


   public static void PrintIndexAndValues(System.Windows.Controls.TextBlock outputBlock, Array myArray)
   {
      for (int i = myArray.GetLowerBound(0); i <= myArray.GetUpperBound(0); i++)
         outputBlock.Text += String.Format("\t[{0}]:\t{1}", i, myArray.GetValue(i)) + "\n";
   }
}
/* 
This code produces the following output.

The Array initially contains the following values:
    [0]:    The
    [1]:    quick
    [2]:    brown
    [3]:    fox
    [4]:    jumps
    [5]:    over
    [6]:    the
    [7]:    lazy
    [8]:    dog
After reversing:
    [0]:    dog
    [1]:    lazy
    [2]:    the
    [3]:    over
    [4]:    jumps
    [5]:    fox
    [6]:    brown
    [7]:    quick
    [8]:    The
*/

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Condividi tramite