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

.NET Framework 3.0

Other Versions

Sorts a range of elements in a pair of one-dimensional Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the specified IComparer.

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

Syntax

C++

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

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

JScript

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

XAML

Not applicable.

Parameters

keys: The one-dimensional Array that contains the keys to sort.

items

The one-dimensional Array that contains the items that correspond to each of the keys in the keysArray.

-or-

a null reference (Nothing in Visual Basic) to sort only the keysArray.

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	keys is a null reference (Nothing in Visual Basic).
RankException	The keysArray is multidimensional. -or- The itemsArray is multidimensional.
ArgumentOutOfRangeException	index is less than the lower bound of keys. -or- length is less than zero.
ArgumentException	items is not a null reference (Nothing in Visual Basic), and the lower bound of keys does not match the lower bound of items. -or- items is not a null reference (Nothing in Visual Basic), and the length of keys does not match the length of items. -or- index and length do not specify a valid range in the keysArray. -or- items is not a null reference (Nothing in Visual Basic), and index and length do not specify a valid range in the itemsArray. -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 the keysArray do not implement the IComparable interface.

Remarks

Each key in the keysArray has a corresponding item in the itemsArray. When a key is repositioned during the sorting, the corresponding item in the itemsArray is similarly repositioned. Therefore, the itemsArray is sorted according to the arrangement of the corresponding keys in the keysArray.

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

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 two associated arrays where the first array contains the keys and the second array contains the values. Sorts are done 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[] myKeys = { "red", "GREEN", "YELLOW", "BLUE", "purple", "black", "orange" };
      String[] myValues = { "strawberries", "PEARS", "LIMES", "BERRIES", "grapes", "olives", "cantaloupe" };
      IComparer myComparer = new myReverserClass();
 
      // Displays the values of the Array.
      Console.WriteLine( "The Array initially contains the following values:" );
      PrintKeysAndValues( myKeys, myValues );
 
      // Sorts a section of the Array using the default comparer.
      Array.Sort( myKeys, myValues, 1, 3 );
      Console.WriteLine( "After sorting a section of the Array using the default comparer:" );
      PrintKeysAndValues( myKeys, myValues );

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

      // Sorts the entire Array using the default comparer.
      Array.Sort( myKeys, myValues );
      Console.WriteLine( "After sorting the entire Array using the default comparer:" );
      PrintKeysAndValues( myKeys, myValues );

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

   }
 
   public static void PrintKeysAndValues( String[] myKeys, String[] myValues )  {
      for ( int i = 0; i < myKeys.Length; i++ )  {
         Console.WriteLine( "   {0,-10}: {1}", myKeys[i], myValues[i] );
      }
      Console.WriteLine();
   }
}


/* 
This code produces the following output.

The Array initially contains the following values:
   red       : strawberries
   GREEN     : PEARS
   YELLOW    : LIMES
   BLUE      : BERRIES
   purple    : grapes
   black     : olives
   orange    : cantaloupe

After sorting a section of the Array using the default comparer:
   red       : strawberries
   BLUE      : BERRIES
   GREEN     : PEARS
   YELLOW    : LIMES
   purple    : grapes
   black     : olives
   orange    : cantaloupe

After sorting a section of the Array using the reverse case-insensitive comparer:
   red       : strawberries
   YELLOW    : LIMES
   GREEN     : PEARS
   BLUE      : BERRIES
   purple    : grapes
   black     : olives
   orange    : cantaloupe

After sorting the entire Array using the default comparer:
   black     : olives
   BLUE      : BERRIES
   GREEN     : PEARS
   orange    : cantaloupe
   purple    : grapes
   red       : strawberries
   YELLOW    : LIMES

After sorting the entire Array using the reverse case-insensitive comparer:
   YELLOW    : LIMES
   red       : strawberries
   purple    : grapes
   orange    : cantaloupe
   GREEN     : PEARS
   BLUE      : BERRIES
   black     : olives

*/

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 myKeys[] = {"red", "GREEN", "YELLOW", "BLUE", "purple", "black",
            "orange" };
        String myValues[] = { "strawberries", "PEARS", "LIMES", "BERRIES", 
            "grapes", "olives", "cantaloupe" };
        IComparer myComparer = new MyReverserClass();

        // Displays the values of the Array.
        Console.WriteLine("The Array initially contains the following values:");
        PrintKeysAndValues(myKeys, myValues);

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

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

        // Sorts the entire Array using the default comparer.
        Array.Sort(myKeys, myValues);
        Console.WriteLine("After sorting the entire Array "
            + "using the default comparer:");
        PrintKeysAndValues(myKeys, myValues);

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

    public static void PrintKeysAndValues(String myKeys[], String myValues[])
    {
        for (int i = 0; i < myKeys.length; i++) {
            Console.WriteLine("   {0,-10}: {1}", myKeys.get_Item(i), 
                myValues.get_Item(i));
        }
        Console.WriteLine();
    } //PrintKeysAndValues
} //SamplesArray
/* 
This code produces the following output.

The Array initially contains the following values:
   red       : strawberries
   GREEN     : PEARS
   YELLOW    : LIMES
   BLUE      : BERRIES
   purple    : grapes
   black     : olives
   orange    : cantaloupe

After sorting a section of the Array using the default comparer:
   red       : strawberries
   BLUE      : BERRIES
   GREEN     : PEARS
   YELLOW    : LIMES
   purple    : grapes
   black     : olives
   orange    : cantaloupe

After sorting a section of the Array using the reverse case-insensitive comparer:
   red       : strawberries
   YELLOW    : LIMES
   GREEN     : PEARS
   BLUE      : BERRIES
   purple    : grapes
   black     : olives
   orange    : cantaloupe

After sorting the entire Array using the default comparer:
   black     : olives
   BLUE      : BERRIES
   GREEN     : PEARS
   orange    : cantaloupe
   purple    : grapes
   red       : strawberries
   YELLOW    : LIMES

After sorting the entire Array using the reverse case-insensitive comparer:
   YELLOW    : LIMES
   red       : strawberries
   purple    : grapes
   orange    : cantaloupe
   GREEN     : PEARS
   BLUE      : BERRIES
   black     : olives

*/

Platforms

Windows 98, Windows Server 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 Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

Version Information

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 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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