Sort Method
.NET Framework Class Library
ArrayList..::.Sort Method

Updated: October 2008

Sorts the elements in the entire ArrayList using the IComparable implementation of each element.

Namespace:  System.Collections
Assembly:  mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
Public Overridable Sub Sort
Visual Basic (Usage)
Dim instance As ArrayList

instance.Sort()
C#
public virtual void Sort()
Visual C++
public:
virtual void Sort()
JScript
public function Sort()
ExceptionCondition
NotSupportedException

The ArrayList is read-only.

This method uses Array..::.Sort, which uses the QuickSort algorithm. The QuickStort algorithm is a comparison sort (also called an unstable sort), which means that a "less than or equal to" comparison operation determines which of two elements should occur first in the final sorted list. However, if two elements are equal, their original order might not be preserved. In contrast, a stable sort preserves the order of elements that are equal. To perform a stable sort, you must implement a custom IComparer interface to use with the other overloads of this method.

On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n^2) operation.

The following code example shows how to sort the values in an ArrayList.

Visual Basic
Imports System
Imports System.Collections

Public Class SamplesArrayList

    Public Shared Sub Main()

        ' Creates and initializes a new ArrayList.
        Dim myAL As New ArrayList()
        myAL.Add("The")
        myAL.Add("quick")
        myAL.Add("brown")
        myAL.Add("fox")
        myAL.Add("jumps")
        myAL.Add("over")
        myAL.Add("the")
        myAL.Add("lazy")
        myAL.Add("dog")

        ' Displays the values of the ArrayList.
        Console.WriteLine("The ArrayList initially contains the following values:")
        PrintValues(myAL)

        ' Sorts the values of the ArrayList.
        myAL.Sort()

        ' Displays the values of the ArrayList.
        Console.WriteLine("After sorting:")
        PrintValues(myAL)

    End Sub 'Main

    Public Shared Sub PrintValues(myList As IEnumerable)
        Dim obj As [Object]
        For Each obj In  myList
            Console.WriteLine("   {0}", obj)
        Next obj
        Console.WriteLine()
    End Sub 'PrintValues

End Class 'SamplesArrayList 


' This code produces the following output.
'
' The ArrayList initially contains the following values:
'    The
'    quick
'    brown
'    fox
'    jumps
'    over
'    the
'    lazy
'    dog
'
' After sorting:
'    brown
'    dog
'    fox
'    jumps
'    lazy
'    over
'    quick
'    the
'    The

C#
using System;
using System.Collections;
public class SamplesArrayList  {

   public static void Main()  {

      // Creates and initializes a new ArrayList.
      ArrayList myAL = new ArrayList();
      myAL.Add( "The" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );
      myAL.Add( "jumps" );
      myAL.Add( "over" );
      myAL.Add( "the" );
      myAL.Add( "lazy" );
      myAL.Add( "dog" );

      // Displays the values of the ArrayList.
      Console.WriteLine( "The ArrayList initially contains the following values:" );
      PrintValues( myAL );

      // Sorts the values of the ArrayList.
      myAL.Sort();

      // Displays the values of the ArrayList.
      Console.WriteLine( "After sorting:" );
      PrintValues( myAL );
   }

   public static void PrintValues( IEnumerable myList )  {
      foreach ( Object obj in myList )
         Console.WriteLine( "   {0}", obj );
      Console.WriteLine();
   }

}


/* 
This code produces the following output.

The ArrayList initially contains the following values:
   The
   quick
   brown
   fox
   jumps
   over
   the
   lazy
   dog

After sorting:
   brown
   dog
   fox
   jumps
   lazy
   over
   quick
   the
   The
*/
Visual C++
using namespace System;
using namespace System::Collections;
void PrintValues( IEnumerable^ myList );
int main()
{

   // Creates and initializes a new ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "The" );
   myAL->Add( "quick" );
   myAL->Add( "brown" );
   myAL->Add( "fox" );
   myAL->Add( "jumps" );
   myAL->Add( "over" );
   myAL->Add( "the" );
   myAL->Add( "lazy" );
   myAL->Add( "dog" );

   // Displays the values of the ArrayList.
   Console::WriteLine( "The ArrayList initially contains the following values:" );
   PrintValues( myAL );

   // Sorts the values of the ArrayList.
   myAL->Sort();

   // Displays the values of the ArrayList.
   Console::WriteLine( "After sorting:" );
   PrintValues( myAL );
}

void PrintValues( IEnumerable^ myList )
{
   IEnumerator^ myEnum = myList->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ obj = safe_cast<Object^>(myEnum->Current);
      Console::WriteLine( "   {0}", obj );
   }

   Console::WriteLine();
}

/* 
 This code produces the following output.

 The ArrayList initially contains the following values:
    The
    quick
    brown
    fox
    jumps
    over
    the
    lazy
    dog

 After sorting:
    brown
    dog
    fox
    jumps
    lazy
    over
    quick
    the
    The
 */
JScript
import System;
import System.Collections;

// Creates and initializes a new ArrayList.
var myAL : ArrayList = new ArrayList();
myAL.Add( "The" );
myAL.Add( "quick" );
myAL.Add( "brown" );
myAL.Add( "fox" );
myAL.Add( "jumped" );
myAL.Add( "over" );
myAL.Add( "the" );
myAL.Add( "lazy" );
myAL.Add( "dog" );

// Displays the values of the ArrayList.
Console.WriteLine( "The ArrayList initially contains the following values:" );
PrintIndexAndValues( myAL );

// Sorts the values of the ArrayList.
myAL.Sort();

// Displays the values of the ArrayList.
Console.WriteLine( "After sorting:" );
PrintIndexAndValues( myAL );

function PrintIndexAndValues( myList : IEnumerable )  {
   var i : int = 0;
   var myEnumerator : System.Collections.IEnumerator  = myList.GetEnumerator();
   while ( myEnumerator.MoveNext() )
      Console.WriteLine( "\t[{0}]:\t{1}", i++, myEnumerator.Current );
   Console.WriteLine();
}
 /* 
 This code produces the following output.

 The ArrayList initially contains the following values:
     [0]:    The
     [1]:    quick
     [2]:    brown
     [3]:    fox
     [4]:    jumped
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog

 After sorting:
     [0]:    brown
     [1]:    dog
     [2]:    fox
     [3]:    jumped
     [4]:    lazy
     [5]:    over
     [6]:    quick
     [7]:    the
     [8]:    The
 */

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

October 2008

Revised the Remarks section to note that the QuickSort algorithm is a comparison sort.

Information enhancement.

Tags What's this?: Add a tag
Community Content   What is Community Content?
Add new content RSS  Annotations
Processing
Page view tracker