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Array.Sort Generic Method (TKey[], TValue[])

Sorts a pair of Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the IComparable generic interface implementation of each key.

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

public static void Sort<TKey,TValue> (
	TKey[] keys,
	TValue[] items
)
J# supports the use of generic types and methods, but not the declaration of new ones.
JScript does not support generic types and methods.
Not applicable.

Type Parameters

TKey

The type of the elements of the key array.

TValue

The type of the elements of the items array.

Parameters

keys

The one-dimensional, zero-based Array that contains the keys to sort.

items

The one-dimensional, zero-based Array that contains the items that correspond to the keys in keys, or a null reference (Nothing in Visual Basic) to sort only keys.

Exception typeCondition

ArgumentNullException

keys is a null reference (Nothing in Visual Basic).

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.

InvalidOperationException

One or more elements in the keysArray do not implement the IComparable generic interface.

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.

Each key in the keysArray must implement the IComparable generic 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 the Length of array; in the worst case it is an O(n ^ 2) operation.

The following code example demonstrates the Sort(J[],K[]), Sort(J[],K[],Generic IComparer), Sort(J[],K[],Int32,Int32), and Sort(J[],K[],Int32,Int32,Generic IComparer) generic method overloads, for sorting pairs of arrays that represent keys and values.

The code example defines an alternative comparer for strings, named ReverseCompare, which implements the IComparer<string> (IComparer(Of String) in Visual Basic, IComparer<String^> in Visual C++) generic interface. The comparer calls the CompareTo(String) method, reversing the order of the comparands so that the strings sort high-to-low instead of low-to-high.

The code example creates and displays an array of dinosaur names (the keys) and an array of integers representing the maximum length of each dinosaur in meters (the values). The arrays are then sorted and displayed several times:

  • The Sort(J[],K[]) overload is used to sort both arrays in order of the dinosaur names in the first array.

  • The Sort(J[],K[],Generic IComparer) overload and an instance of ReverseCompare are used to reverse the sort order of the paired arrays.

  • The Sort(J[],K[],Int32,Int32) overload is used to sort the last three elements of both arrays.

  • The Sort(J[],K[],Int32,Int32,Generic IComparer) overload is used to sort the last three elements of both arrays in reverse order.

NoteNote:

The calls to the generic methods do not look any different from calls to their nongeneric counterparts, because Visual Basic, C#, and C++ infer the type of the generic type parameter from the type of the first two arguments. If you use the MSIL Disassembler (Ildasm.exe) to examine the Microsoft intermediate language (MSIL), you can see that the generic methods are being called.

using System;
using System.Collections.Generic;

public class ReverseComparer: IComparer<string>
{
    public int Compare(string x, string y)
    {
        // Compare y and x in reverse order.
        return y.CompareTo(x);
    }
}

public class Example
{
    public static void Main()
    {
        string[] dinosaurs = {
            "Seismosaurus", 
            "Chasmosaurus", 
            "Coelophysis", 
            "Mamenchisaurus", 
            "Caudipteryx", 
            "Cetiosaurus"  };

        int[] dinosaurSizes = { 40, 5, 3, 22, 1, 18 };

        Console.WriteLine();
        for (int i = 0; i < dinosaurs.Length; i++)
        {
            Console.WriteLine("{0}: up to {1} meters long.", 
                dinosaurs[i], dinosaurSizes[i]);
        }

        Console.WriteLine("\nSort(dinosaurs, dinosaurSizes)");
        Array.Sort(dinosaurs, dinosaurSizes);

        Console.WriteLine();
        for (int i = 0; i < dinosaurs.Length; i++)
        {
            Console.WriteLine("{0}: up to {1} meters long.", 
                dinosaurs[i], dinosaurSizes[i]);
        }

        ReverseComparer rc = new ReverseComparer();

        Console.WriteLine("\nSort(dinosaurs, dinosaurSizes, rc)");
        Array.Sort(dinosaurs, dinosaurSizes, rc);

        Console.WriteLine();
        for (int i = 0; i < dinosaurs.Length; i++)
        {
            Console.WriteLine("{0}: up to {1} meters long.", 
                dinosaurs[i], dinosaurSizes[i]);
        }

        Console.WriteLine("\nSort(dinosaurs, dinosaurSizes, 3, 3)");
        Array.Sort(dinosaurs, dinosaurSizes, 3, 3);

        Console.WriteLine();
        for (int i = 0; i < dinosaurs.Length; i++)
        {
            Console.WriteLine("{0}: up to {1} meters long.", 
                dinosaurs[i], dinosaurSizes[i]);
        }

        Console.WriteLine("\nSort(dinosaurs, dinosaurSizes, 3, 3, rc)");
        Array.Sort(dinosaurs, dinosaurSizes, 3, 3, rc);

        Console.WriteLine();
        for (int i = 0; i < dinosaurs.Length; i++)
        {
            Console.WriteLine("{0}: up to {1} meters long.", 
                dinosaurs[i], dinosaurSizes[i]);
        }
    }
}

/* This code example produces the following output:

Seismosaurus: up to 40 meters long.
Chasmosaurus: up to 5 meters long.
Coelophysis: up to 3 meters long.
Mamenchisaurus: up to 22 meters long.
Caudipteryx: up to 1 meters long.
Cetiosaurus: up to 18 meters long.

Sort(dinosaurs, dinosaurSizes)

Caudipteryx: up to 1 meters long.
Cetiosaurus: up to 18 meters long.
Chasmosaurus: up to 5 meters long.
Coelophysis: up to 3 meters long.
Mamenchisaurus: up to 22 meters long.
Seismosaurus: up to 40 meters long.

Sort(dinosaurs, dinosaurSizes, rc)

Seismosaurus: up to 40 meters long.
Mamenchisaurus: up to 22 meters long.
Coelophysis: up to 3 meters long.
Chasmosaurus: up to 5 meters long.
Cetiosaurus: up to 18 meters long.
Caudipteryx: up to 1 meters long.

Sort(dinosaurs, dinosaurSizes, 3, 3)

Seismosaurus: up to 40 meters long.
Mamenchisaurus: up to 22 meters long.
Coelophysis: up to 3 meters long.
Caudipteryx: up to 1 meters long.
Cetiosaurus: up to 18 meters long.
Chasmosaurus: up to 5 meters long.

Sort(dinosaurs, dinosaurSizes, 3, 3, rc)

Seismosaurus: up to 40 meters long.
Mamenchisaurus: up to 22 meters long.
Coelophysis: up to 3 meters long.
Chasmosaurus: up to 5 meters long.
Cetiosaurus: up to 18 meters long.
Caudipteryx: up to 1 meters long.
 */

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.

.NET Framework

Supported in: 3.0, 2.0

.NET Compact Framework

Supported in: 2.0

XNA Framework

Supported in: 1.0

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