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Array.Sort Method (Array, Int32, Int32, IComparer)

.NET Framework 2.0

Sorts the elements in a range of elements in a one-dimensional Array using the specified IComparer.

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

public static void Sort (
	Array array,
	int index,
	int length,
	IComparer comparer
)

public static void Sort (
	Array array, 
	int index, 
	int length, 
	IComparer comparer
)

JScript

public static function Sort (
	array : Array, 
	index : int, 
	length : int, 
	comparer : IComparer
)

Parameters

array: The one-dimensional Array to sort.

index: The starting index of the range to sort.

length: The number of elements in the range to sort.

comparer

The IComparer implementation to use when comparing elements.

-or-

a null reference (Nothing in Visual Basic) to use the IComparable implementation of each element.

Exceptions

Exception type	Condition
ArgumentNullException	array is a null reference (Nothing in Visual Basic).
RankException	array is multidimensional.
ArgumentOutOfRangeException	index is less than the lower bound of array. -or- length is less than zero.
ArgumentException	index and length do not specify a valid range in array. -or- The implementation of comparer caused an error during the sort. For example, comparer might not return 0 when comparing an item with itself.
InvalidOperationException	comparer is a null reference (Nothing in Visual Basic), and one or more elements in array do not implement the IComparable interface.

Remarks

If comparer is a null reference (Nothing in Visual Basic), each element within the specified range of elements in array must implement the IComparable interface to be capable of comparisons with every other element in array.

If the sort is not successfully completed, the results are undefined.

This method uses the QuickSort algorithm. This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. In contrast, a stable sort preserves the order of elements that are equal.

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

Example

The following code example shows how to sort the values in an Array using the default comparer and a custom comparer that reverses the sort order. Note that the result might vary depending on the current CultureInfo.

C++

using System;
using System.Collections;

public class SamplesArray  {
 
   public class myReverserClass : IComparer  {

      // Calls CaseInsensitiveComparer.Compare with the parameters reversed.
      int IComparer.Compare( Object x, Object y )  {
          return( (new CaseInsensitiveComparer()).Compare( y, x ) );
      }

   }

   public static void Main()  {
 
      // Creates and initializes a new Array and a new custom comparer.
      String[] myArr = { "The", "QUICK", "BROWN", "FOX", "jumps", "over", "the", "lazy", "dog" };
      IComparer myComparer = new myReverserClass();
 
      // Displays the values of the Array.
      Console.WriteLine( "The Array initially contains the following values:" );
      PrintIndexAndValues( myArr );
 
      // Sorts a section of the Array using the default comparer.
      Array.Sort( myArr, 1, 3 );
      Console.WriteLine( "After sorting a section of the Array using the default comparer:" );
      PrintIndexAndValues( myArr );

      // Sorts a section of the Array using the reverse case-insensitive comparer.
      Array.Sort( myArr, 1, 3, myComparer );
      Console.WriteLine( "After sorting a section of the Array using the reverse case-insensitive comparer:" );
      PrintIndexAndValues( myArr );

      // Sorts the entire Array using the default comparer.
      Array.Sort( myArr );
      Console.WriteLine( "After sorting the entire Array using the default comparer:" );
      PrintIndexAndValues( myArr );

      // Sorts the entire Array using the reverse case-insensitive comparer.
      Array.Sort( myArr, myComparer );
      Console.WriteLine( "After sorting the entire Array using the reverse case-insensitive comparer:" );
      PrintIndexAndValues( myArr );

   }
 
   public static void PrintIndexAndValues( String[] myArr )  {
      for ( int i = 0; i < myArr.Length; i++ )  {
         Console.WriteLine( "   [{0}] : {1}", i, myArr[i] );
      }
      Console.WriteLine();
   }
}


/* 
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 sorting a section of the Array using the default comparer:
   [0] : The
   [1] : BROWN
   [2] : FOX
   [3] : QUICK
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting a section of the Array using the reverse case-insensitive comparer:
   [0] : The
   [1] : QUICK
   [2] : FOX
   [3] : BROWN
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting the entire Array using the default comparer:
   [0] : BROWN
   [1] : dog
   [2] : FOX
   [3] : jumps
   [4] : lazy
   [5] : over
   [6] : QUICK
   [7] : the
   [8] : The

After sorting the entire Array using the reverse case-insensitive comparer:
   [0] : the
   [1] : The
   [2] : QUICK
   [3] : over
   [4] : lazy
   [5] : jumps
   [6] : FOX
   [7] : dog
   [8] : BROWN

*/

import System.*;
import System.Collections.*;

public class SamplesArray
{
    public static class MyReverserClass implements IComparer
    {
        // Calls CaseInsensitiveComparer.Compare with the parameters reversed.
        public int Compare(Object x, Object y)
        {
            return (new CaseInsensitiveComparer()).Compare(y, x);
        } //IComparer.Compare
    } //MyReverserClass

    public static void main(String[] args)
    {
        // Creates and initializes a new Array and a new custom comparer.
        String myArr[] = { "The", "QUICK", "BROWN", "FOX", "jumps", "over", 
            "the", "lazy", "dog" };
        IComparer myComparer = new MyReverserClass();

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

        // Sorts a section of the Array using the default comparer.
        Array.Sort(myArr, 1, 3);
        Console.WriteLine("After sorting a section of the Array using the"  
            + " default comparer:");
        PrintIndexAndValues(myArr);

        // Sorts a section of the Array using the reverse case-insensitive 
        // comparer.
        Array.Sort(myArr, 1, 3, myComparer);
        Console.WriteLine("After sorting a section of the Array using the"  
            + " reverse case-insensitive comparer:");
        PrintIndexAndValues(myArr);

        // Sorts the entire Array using the default comparer.
        Array.Sort(myArr);
        Console.WriteLine("After sorting the entire Array using the default"  
            + " comparer:");
        PrintIndexAndValues(myArr);

        // Sorts the entire Array using the reverse case-insensitive comparer.
        Array.Sort(myArr, myComparer);
        Console.WriteLine("After sorting the entire Array using the reverse "  
            + "case-insensitive comparer:");
        PrintIndexAndValues(myArr);
    } //main

    public static void PrintIndexAndValues(String myArr[])
    {
        for (int i = 0; i < myArr.length; i++) {
            Console.WriteLine("   [{0}] : {1}", System.Convert.ToString(i), 
                myArr.get_Item(i));
        }
        Console.WriteLine();
    } //PrintIndexAndValues
} //SamplesArray
/* 
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 sorting a section of the Array using the default comparer:
   [0] : The
   [1] : BROWN
   [2] : FOX
   [3] : QUICK
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting a section of the Array using the reverse case-insensitive 
comparer:
   [0] : The
   [1] : QUICK
   [2] : FOX
   [3] : BROWN
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

After sorting the entire Array using the default comparer:
   [0] : BROWN
   [1] : dog
   [2] : FOX
   [3] : jumps
   [4] : lazy
   [5] : over
   [6] : QUICK
   [7] : the
   [8] : The

After sorting the entire Array using the reverse case-insensitive comparer:
   [0] : the
   [1] : The
   [2] : QUICK
   [3] : over
   [4] : lazy
   [5] : jumps
   [6] : FOX
   [7] : dog
   [8] : BROWN

*/

Platforms

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

Version Information

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

Reference

Array Class
Array Members
System Namespace
IComparer
IComparable
BinarySearch

Other Resources

Performing Culture-Insensitive String Operations in Arrays

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