ArrayList.Sort Method
Important
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Sorts the elements in the ArrayList or a portion of it.
| Sort() |
Sorts the elements in the entire ArrayList. |
| Sort(IComparer) |
Sorts the elements in the entire ArrayList using the specified comparer. |
| Sort(Int32, Int32, IComparer) |
Sorts the elements in a range of elements in ArrayList using the specified comparer. |
- Source:
- ArrayList.cs
- Source:
- ArrayList.cs
- Source:
- ArrayList.cs
Sorts the elements in the entire ArrayList.
public:
virtual void Sort();C#
public virtual void Sort();abstract member Sort : unit -> unit
override this.Sort : unit -> unitPublic Overridable Sub Sort ()Exceptions
The ArrayList is read-only.
Examples
The following code example shows how to sort the values in an ArrayList.
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
*/
C#
using System;
using System.Collections;
public class SamplesArrayList1
{
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
*/
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
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
End Class
' 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
Remarks
This method uses Array.Sort, which uses the QuickSort algorithm. The QuickSort 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.
See also
Applies to
.NET 10 and other versions
| Product | Versions |
|---|---|
| .NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10 |
| .NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 2.0, 2.1 |
| UWP | 10.0 |
- Source:
- ArrayList.cs
- Source:
- ArrayList.cs
- Source:
- ArrayList.cs
Sorts the elements in the entire ArrayList using the specified comparer.
public:
virtual void Sort(System::Collections::IComparer ^ comparer);C#
public virtual void Sort(System.Collections.IComparer comparer);C#
public virtual void Sort(System.Collections.IComparer? comparer);abstract member Sort : System.Collections.IComparer -> unit
override this.Sort : System.Collections.IComparer -> unitPublic Overridable Sub Sort (comparer As IComparer)Parameters
- comparer
- IComparer
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
The ArrayList is read-only.
An error occurred while comparing two elements.
null is passed for comparer, and the elements in the list do not implement IComparable.
Examples
The following code example shows how to sort the values in an ArrayList using the default comparer and a custom comparer that reverses the sort order.
using namespace System;
using namespace System::Collections;
void PrintIndexAndValues( IEnumerable^ myList );
ref class myReverserClass: public IComparer
{
private:
// Calls CaseInsensitiveComparer.Compare with the parameters reversed.
virtual int Compare( Object^ x, Object^ y ) sealed = IComparer::Compare
{
return ((gcnew CaseInsensitiveComparer)->Compare( y, x ));
}
};
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:" );
PrintIndexAndValues( myAL );
// Sorts the values of the ArrayList using the default comparer.
myAL->Sort();
Console::WriteLine( "After sorting with the default comparer:" );
PrintIndexAndValues( myAL );
// Sorts the values of the ArrayList using the reverse case-insensitive comparer.
IComparer^ myComparer = gcnew myReverserClass;
myAL->Sort( myComparer );
Console::WriteLine( "After sorting with the reverse case-insensitive comparer:" );
PrintIndexAndValues( myAL );
}
void PrintIndexAndValues( IEnumerable^ myList )
{
int i = 0;
IEnumerator^ myEnum = myList->GetEnumerator();
while ( myEnum->MoveNext() )
{
Object^ obj = safe_cast<Object^>(myEnum->Current);
Console::WriteLine( "\t[{0}]:\t{1}", i++, obj );
}
Console::WriteLine();
}
/*
This code produces the following output.
The ArrayList 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 with the default comparer:
[0]: brown
[1]: dog
[2]: fox
[3]: jumps
[4]: lazy
[5]: over
[6]: quick
[7]: the
[8]: The
After sorting with the reverse case-insensitive comparer:
[0]: the
[1]: The
[2]: quick
[3]: over
[4]: lazy
[5]: jumps
[6]: fox
[7]: dog
[8]: brown
*/
C#
using System;
using System.Collections;
public class SamplesArrayList2
{
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 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:");
PrintIndexAndValues(myAL);
// Sorts the values of the ArrayList using the default comparer.
myAL.Sort();
Console.WriteLine("After sorting with the default comparer:");
PrintIndexAndValues(myAL);
// Sorts the values of the ArrayList using the reverse case-insensitive comparer.
IComparer myComparer = new myReverserClass();
myAL.Sort(myComparer);
Console.WriteLine("After sorting with the reverse case-insensitive comparer:");
PrintIndexAndValues(myAL);
}
public static void PrintIndexAndValues(IEnumerable myList)
{
int i = 0;
foreach (Object obj in myList)
Console.WriteLine("\t[{0}]:\t{1}", i++, obj);
Console.WriteLine();
}
}
/*
This code produces the following output.
The ArrayList 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 with the default comparer:
[0]: brown
[1]: dog
[2]: fox
[3]: jumps
[4]: lazy
[5]: over
[6]: quick
[7]: the
[8]: The
After sorting with the reverse case-insensitive comparer:
[0]: the
[1]: The
[2]: quick
[3]: over
[4]: lazy
[5]: jumps
[6]: fox
[7]: dog
[8]: brown
*/
Imports System.Collections
Public Class SamplesArrayList
Public Class myReverserClass
Implements IComparer
' Calls CaseInsensitiveComparer.Compare with the parameters reversed.
Public Function Compare( ByVal x As Object, ByVal y As Object) As Integer _
Implements IComparer.Compare
Return New CaseInsensitiveComparer().Compare(y, x)
End Function 'IComparer.Compare
End Class
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:")
PrintIndexAndValues(myAL)
' Sorts the values of the ArrayList using the default comparer.
myAL.Sort()
Console.WriteLine("After sorting with the default comparer:")
PrintIndexAndValues(myAL)
' Sorts the values of the ArrayList using the reverse case-insensitive comparer.
Dim myComparer = New myReverserClass()
myAL.Sort(myComparer)
Console.WriteLine("After sorting with the reverse case-insensitive comparer:")
PrintIndexAndValues(myAL)
End Sub
Public Shared Sub PrintIndexAndValues(myList As IEnumerable)
Dim i As Integer = 0
Dim obj As [Object]
For Each obj In myList
Console.WriteLine(vbTab + "[{0}]:" + vbTab + "{1}", i, obj)
i = i + 1
Next obj
Console.WriteLine()
End Sub
End Class
'This code produces the following output.
'The ArrayList 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 with the default comparer:
' [0]: brown
' [1]: dog
' [2]: fox
' [3]: jumps
' [4]: lazy
' [5]: over
' [6]: quick
' [7]: the
' [8]: The
'
'After sorting with the reverse case-insensitive comparer:
' [0]: the
' [1]: The
' [2]: quick
' [3]: over
' [4]: lazy
' [5]: jumps
' [6]: fox
' [7]: dog
' [8]: brown
Remarks
Use the Sort method to sort a list of objects with a custom comparer that implements the IComparer interface. If you pass null for comparer, this method uses the IComparable implementation of each element. In this case, you must make sure that the objects contained in the list implement the IComparer interface or an exception will occur.
In addition, using the IComparable implementation means the list performs a comparison sort (also called 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. To perform a stable sort, you must implement a custom IComparer interface.
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.
See also
Applies to
.NET 10 and other versions
| Product | Versions |
|---|---|
| .NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10 |
| .NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 2.0, 2.1 |
| UWP | 10.0 |
- Source:
- ArrayList.cs
- Source:
- ArrayList.cs
- Source:
- ArrayList.cs
Sorts the elements in a range of elements in ArrayList using the specified comparer.
public:
virtual void Sort(int index, int count, System::Collections::IComparer ^ comparer);C#
public virtual void Sort(int index, int count, System.Collections.IComparer comparer);C#
public virtual void Sort(int index, int count, System.Collections.IComparer? comparer);abstract member Sort : int * int * System.Collections.IComparer -> unit
override this.Sort : int * int * System.Collections.IComparer -> unitPublic Overridable Sub Sort (index As Integer, count As Integer, comparer As IComparer)Parameters
- index
- Int32
The zero-based starting index of the range to sort.
- count
- Int32
The length of the range to sort.
- comparer
- IComparer
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
index and count do not specify a valid range in the ArrayList.
The ArrayList is read-only.
An error occurred while comparing two elements.
Examples
The following code example shows how to sort the values in a range of elements in an ArrayList using the default comparer and a custom comparer that reverses the sort order.
using namespace System;
using namespace System::Collections;
void PrintIndexAndValues( IEnumerable^ myList );
ref class myReverserClass: public IComparer
{
private:
// Calls CaseInsensitiveComparer.Compare with the parameters reversed.
virtual int Compare( Object^ x, Object^ y ) = IComparer::Compare
{
return ((gcnew CaseInsensitiveComparer)->Compare( y, x ));
}
};
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:" );
PrintIndexAndValues( myAL );
// Sorts the values of the ArrayList using the default comparer.
myAL->Sort( 1, 3, nullptr );
Console::WriteLine( "After sorting from index 1 to index 3 with the default comparer:" );
PrintIndexAndValues( myAL );
// Sorts the values of the ArrayList using the reverse case-insensitive comparer.
IComparer^ myComparer = gcnew myReverserClass;
myAL->Sort( 1, 3, myComparer );
Console::WriteLine( "After sorting from index 1 to index 3 with the reverse case-insensitive comparer:" );
PrintIndexAndValues( myAL );
}
void PrintIndexAndValues( IEnumerable^ myList )
{
int i = 0;
IEnumerator^ myEnum = myList->GetEnumerator();
while ( myEnum->MoveNext() )
{
Object^ obj = safe_cast<Object^>(myEnum->Current);
Console::WriteLine( "\t[{0}]:\t{1}", i++, obj );
}
Console::WriteLine();
}
/*
This code produces the following output.
The ArrayList 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 from index 1 to index 3 with the default comparer:
[0]: The
[1]: BROWN
[2]: FOX
[3]: QUICK
[4]: jumps
[5]: over
[6]: the
[7]: lazy
[8]: dog
After sorting from index 1 to index 3 with the reverse case-insensitive comparer:
[0]: The
[1]: QUICK
[2]: FOX
[3]: BROWN
[4]: jumps
[5]: over
[6]: the
[7]: lazy
[8]: dog
*/
C#
using System;
using System.Collections;
public class SamplesArrayList3
{
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 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:");
PrintIndexAndValues(myAL);
// Sorts the values of the ArrayList using the default comparer.
myAL.Sort(1, 3, null);
Console.WriteLine("After sorting from index 1 to index 3 with the default comparer:");
PrintIndexAndValues(myAL);
// Sorts the values of the ArrayList using the reverse case-insensitive comparer.
IComparer myComparer = new myReverserClass();
myAL.Sort(1, 3, myComparer);
Console.WriteLine("After sorting from index 1 to index 3 with the reverse case-insensitive comparer:");
PrintIndexAndValues(myAL);
}
public static void PrintIndexAndValues(IEnumerable myList)
{
int i = 0;
foreach (Object obj in myList)
Console.WriteLine("\t[{0}]:\t{1}", i++, obj);
Console.WriteLine();
}
}
/*
This code produces the following output.
The ArrayList 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 from index 1 to index 3 with the default comparer:
[0]: The
[1]: BROWN
[2]: FOX
[3]: QUICK
[4]: jumps
[5]: over
[6]: the
[7]: lazy
[8]: dog
After sorting from index 1 to index 3 with the reverse case-insensitive comparer:
[0]: The
[1]: QUICK
[2]: FOX
[3]: BROWN
[4]: jumps
[5]: over
[6]: the
[7]: lazy
[8]: dog
*/
Imports System.Collections
Public Class SamplesArrayList
Public Class myReverserClass
Implements IComparer
' Calls CaseInsensitiveComparer.Compare with the parameters reversed.
Public Function Compare( ByVal x As Object, ByVal y As Object) As Integer _
Implements IComparer.Compare
Return New CaseInsensitiveComparer().Compare(y, x)
End Function 'IComparer.Compare
End Class
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:")
PrintIndexAndValues(myAL)
' Sorts the values of the ArrayList using the default comparer.
myAL.Sort(1, 3, Nothing)
Console.WriteLine("After sorting from index 1 to index 3 with the default comparer:")
PrintIndexAndValues(myAL)
' Sorts the values of the ArrayList using the reverse case-insensitive comparer.
Dim myComparer = New myReverserClass()
myAL.Sort(1, 3, myComparer)
Console.WriteLine("After sorting from index 1 to index 3 with the reverse case-insensitive comparer:")
PrintIndexAndValues(myAL)
End Sub
Public Shared Sub PrintIndexAndValues(myList As IEnumerable)
Dim i As Integer = 0
Dim obj As [Object]
For Each obj In myList
Console.WriteLine(vbTab + "[{0}]:" + vbTab + "{1}", i, obj)
i = i + 1
Next obj
Console.WriteLine()
End Sub
End Class
'This code produces the following output.
'The ArrayList 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 from index 1 to index 3 with the default comparer:
' [0]: The
' [1]: BROWN
' [2]: FOX
' [3]: QUICK
' [4]: jumps
' [5]: over
' [6]: the
' [7]: lazy
' [8]: dog
'
'After sorting from index 1 to index 3 with the reverse case-insensitive comparer:
' [0]: The
' [1]: QUICK
' [2]: FOX
' [3]: BROWN
' [4]: jumps
' [5]: over
' [6]: the
' [7]: lazy
' [8]: dog
Remarks
If comparer is set to null, this method performs a comparison sort (also called 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. To perform a stable sort, you must implement a custom IComparer interface.
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.
See also
Applies to
.NET 10 and other versions
| Product | Versions |
|---|---|
| .NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10 |
| .NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 2.0, 2.1 |
| UWP | 10.0 |
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