List<T>.Sort メソッド

定義

IComparer<T> の指定した実装または既定の実装を使用するか、リストの要素を比較する指定した Comparison<T> デリゲートを使用して、List<T> の要素または要素の一部を並べ替えます。Sorts the elements or a portion of the elements in the List<T> using either the specified or default IComparer<T> implementation or a provided Comparison<T> delegate to compare list elements.

オーバーロード

Sort(Comparison<T>)

指定した Comparison<T> を使用して、List<T> 全体内の要素を並べ替えます。Sorts the elements in the entire List<T> using the specified Comparison<T>.

Sort(Int32, Int32, IComparer<T>)

指定した比較子を使用して、List<T> 内の要素の範囲内の要素を並べ替えます。Sorts the elements in a range of elements in List<T> using the specified comparer.

Sort()

既定の比較子を使用して、List<T> 全体内の要素を並べ替えます。Sorts the elements in the entire List<T> using the default comparer.

Sort(IComparer<T>)

指定した比較子を使用して、List<T> 全体内の要素を並べ替えます。Sorts the elements in the entire List<T> using the specified comparer.

Sort(Comparison<T>)

指定した Comparison<T> を使用して、List<T> 全体内の要素を並べ替えます。Sorts the elements in the entire List<T> using the specified Comparison<T>.

public:
 void Sort(Comparison<T> ^ comparison);
public void Sort (Comparison<T> comparison);
member this.Sort : Comparison<'T> -> unit
Public Sub Sort (comparison As Comparison(Of T))

パラメーター

comparison
Comparison<T>

要素を比較する場合に使用する Comparison<T>The Comparison<T> to use when comparing elements.

例外

comparisonnull です。comparison is null.

comparison の実装により、並べ替え中にエラーが発生しました。The implementation of comparison caused an error during the sort. たとえば、comparison は、項目をそれ自体と比較したときに 0 を返さなかった可能性があります。For example, comparison might not return 0 when comparing an item with itself.

次のコードは、単純なビジネスオブジェクトでの SortSort メソッドのオーバーロードを示しています。The following code demonstrates the Sort and Sort method overloads on a simple business object. Sort メソッドを呼び出すと、パート型の既定の比較子が使用され、Sort メソッドは匿名メソッドを使用して実装されます。Calling the Sort method results in the use of the default comparer for the Part type, and the Sort method is implemented using an anonymous method.

using System;
using System.Collections.Generic;
// Simple business object. A PartId is used to identify the type of part 
// but the part name can change. 
public class Part : IEquatable<Part> , IComparable<Part>
{
    public string PartName { get; set; }

    public int PartId { get; set; }

    public override string ToString()
    {
        return "ID: " + PartId + "   Name: " + PartName;
    }
    public override bool Equals(object obj)
    {
        if (obj == null) return false;
        Part objAsPart = obj as Part;
        if (objAsPart == null) return false;
        else return Equals(objAsPart);
    }
    public int SortByNameAscending(string name1, string name2)
    {
        
        return name1.CompareTo(name2);
    }

    // Default comparer for Part type.
    public int CompareTo(Part comparePart)
    {
          // A null value means that this object is greater.
        if (comparePart == null)
            return 1;
            
        else
            return this.PartId.CompareTo(comparePart.PartId);
    }
    public override int GetHashCode()
    {
        return PartId;
    }
    public bool Equals(Part other)
    {
        if (other == null) return false;
        return (this.PartId.Equals(other.PartId));
    }
    // Should also override == and != operators.

}
public class Example
{
    public static void Main()
    {
        // Create a list of parts.
        List<Part> parts = new List<Part>();

        // Add parts to the list.
        parts.Add(new Part() { PartName = "regular seat", PartId = 1434 });
        parts.Add(new Part() { PartName= "crank arm", PartId = 1234 });
        parts.Add(new Part() { PartName = "shift lever", PartId = 1634 }); ;
        // Name intentionally left null.
        parts.Add(new Part() {  PartId = 1334 });
        parts.Add(new Part() { PartName = "banana seat", PartId = 1444 });
        parts.Add(new Part() { PartName = "cassette", PartId = 1534 });
       

        // Write out the parts in the list. This will call the overridden 
        // ToString method in the Part class.
        Console.WriteLine("\nBefore sort:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }


        // Call Sort on the list. This will use the 
        // default comparer, which is the Compare method 
        // implemented on Part.
        parts.Sort();


        Console.WriteLine("\nAfter sort by part number:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }
       
        // This shows calling the Sort(Comparison(T) overload using 
        // an anonymous method for the Comparison delegate. 
        // This method treats null as the lesser of two values.
        parts.Sort(delegate(Part x, Part y)
        {
            if (x.PartName == null && y.PartName == null) return 0;
            else if (x.PartName == null) return -1;
            else if (y.PartName == null) return 1;
            else return x.PartName.CompareTo(y.PartName);
        });

        Console.WriteLine("\nAfter sort by name:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }
       
        /*
       
            Before sort:
        ID: 1434   Name: regular seat
        ID: 1234   Name: crank arm
        ID: 1634   Name: shift lever
        ID: 1334   Name:
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette

        After sort by part number:
        ID: 1234   Name: crank arm
        ID: 1334   Name:
        ID: 1434   Name: regular seat
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette
        ID: 1634   Name: shift lever

        After sort by name:
        ID: 1334   Name:
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette
        ID: 1234   Name: crank arm
        ID: 1434   Name: regular seat
        ID: 1634   Name: shift lever

         */

    }
}
Imports System.Collections.Generic

' Simple business object. A PartId is used to identify the type of part 
' but the part name can change. 
Public Class Part
    Implements IEquatable(Of Part)
    Implements IComparable(Of Part)
    Public Property PartName() As String
        Get
            Return m_PartName
        End Get
        Set(value As String)
            m_PartName = Value
        End Set
    End Property
    Private m_PartName As String

    Public Property PartId() As Integer
        Get
            Return m_PartId
        End Get
        Set(value As Integer)
            m_PartId = Value
        End Set
    End Property
    Private m_PartId As Integer

    Public Overrides Function ToString() As String
        Return "ID: " & PartId & "   Name: " & PartName
    End Function

    Public Overrides Function Equals(obj As Object) As Boolean
        If obj Is Nothing Then
            Return False
        End If
        Dim objAsPart As Part = TryCast(obj, Part)
        If objAsPart Is Nothing Then
            Return False
        Else
            Return Equals(objAsPart)
        End If
    End Function

    Public Function SortByNameAscending(name1 As String, name2 As String) As Integer

        Return name1.CompareTo(name2)
    End Function

    ' Default comparer for Part.
    Public Function CompareTo(comparePart As Part) As Integer _
            Implements IComparable(Of ListSortVB.Part).CompareTo
        ' A null value means that this object is greater.
        If comparePart Is Nothing Then
            Return 1
        Else

            Return Me.PartId.CompareTo(comparePart.PartId)
        End If
    End Function
    Public Overrides Function GetHashCode() As Integer
        Return PartId
    End Function
    Public Overloads Function Equals(other As Part) As Boolean Implements IEquatable(Of ListSortVB.Part).Equals
        If other Is Nothing Then
            Return False
        End If
        Return (Me.PartId.Equals(other.PartId))
    End Function
    ' Should also override == and != operators.

End Class
Public Class Example
    Public Shared Sub Main()
        ' Create a list of parts.
        Dim parts As New List(Of Part)()

        ' Add parts to the list.
        parts.Add(New Part() With { _
             .PartName = "regular seat", _
             .PartId = 1434 _
        })
        parts.Add(New Part() With { _
             .PartName = "crank arm", _
             .PartId = 1234 _
        })
        parts.Add(New Part() With { _
             .PartName = "shift lever", _
             .PartId = 1634 _
        })


        ' Name intentionally left null.
        parts.Add(New Part() With { _
             .PartId = 1334 _
        })
        parts.Add(New Part() With { _
             .PartName = "banana seat", _
             .PartId = 1444 _
        })
        parts.Add(New Part() With { _
             .PartName = "cassette", _
             .PartId = 1534 _
        })


        ' Write out the parts in the list. This will call the overridden 
        ' ToString method in the Part class.
        Console.WriteLine(vbLf & "Before sort:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next


        ' Call Sort on the list. This will use the 
        ' default comparer, which is the Compare method 
        ' implemented on Part.
        parts.Sort()


        Console.WriteLine(vbLf & "After sort by part number:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next

        ' This shows calling the Sort(Comparison(T) overload using 
        ' an anonymous delegate method. 
        ' This method treats null as the lesser of two values.
        parts.Sort(Function(x As Part, y As Part)
                             If x.PartName Is Nothing AndAlso y.PartName Is Nothing Then
                                 Return 0
                             ElseIf x.PartName Is Nothing Then
                                 Return -1
                             ElseIf y.PartName Is Nothing Then
                                 Return 1
                             Else
                                 Return x.PartName.CompareTo(y.PartName)
                             End If
                         End Function)
        

        Console.WriteLine(vbLf & "After sort by name:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next

        '
        '        
        '            Before sort:
        '            ID: 1434   Name: regular seat
        '            ID: 1234   Name: crank arm
        '            ID: 1634   Name: shift lever
        '            ID: 1334   Name:
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '
        '            After sort by part number:
        '            ID: 1234   Name: crank arm
        '            ID: 1334   Name:
        '            ID: 1434   Name: regular seat
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '            ID: 1634   Name: shift lever
        '
        '            After sort by name:
        '            ID: 1334   Name:
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '            ID: 1234   Name: crank arm
        '            ID: 1434   Name: regular seat
        '            ID: 1634   Name: shift lever

    End Sub
End Class

次の例は、Sort(Comparison<T>) メソッドのオーバーロードを示しています。The following example demonstrates the Sort(Comparison<T>) method overload.

この例では、CompareDinosByLengthという名前の文字列に対して、別の比較メソッドを定義しています。The example defines an alternative comparison method for strings, named CompareDinosByLength. この方法は次のように機能します。まず、比較対照値が nullに対してテストされ、null 参照が null 以外の値として処理されます。This method works as follows: First, the comparands are tested for null, and a null reference is treated as less than a non-null. 次に、文字列の長さが比較され、長い方の文字列が大きいと見なされます。Second, the string lengths are compared, and the longer string is deemed to be greater. 3番目の長さが等しい場合は、通常の文字列比較が使用されます。Third, if the lengths are equal, ordinary string comparison is used.

文字列の List<T> が作成され、特定の順序ではなく4つの文字列が設定されます。A List<T> of strings is created and populated with four strings, in no particular order. この一覧には、空の文字列と null 参照も含まれています。The list also includes an empty string and a null reference. リストが表示され、CompareDinosByLength メソッドを表す Comparison<T> 汎用デリゲートを使用して並べ替えられて、もう一度表示されます。The list is displayed, sorted using a Comparison<T> generic delegate representing the CompareDinosByLength method, and displayed again.

using namespace System;
using namespace System::Collections::Generic;

int CompareDinosByLength(String^ x, String^ y)
{
    if (x == nullptr)
    {
        if (y == nullptr)
        {
            // If x is null and y is null, they're
            // equal. 
            return 0;
        }
        else
        {
            // If x is null and y is not null, y
            // is greater. 
            return -1;
        }
    }
    else
    {
        // If x is not null...
        //
        if (y == nullptr)
            // ...and y is null, x is greater.
        {
            return 1;
        }
        else
        {
            // ...and y is not null, compare the 
            // lengths of the two strings.
            //
            int retval = x->Length.CompareTo(y->Length);

            if (retval != 0)
            {
                // If the strings are not of equal length,
                // the longer string is greater.
                //
                return retval;
            }
            else
            {
                // If the strings are of equal length,
                // sort them with ordinary string comparison.
                //
                return x->CompareTo(y);
            }
        }
    }
};

void Display(List<String^>^ list)
{
    Console::WriteLine();
    for each(String^ s in list)
    {
        if (s == nullptr)
            Console::WriteLine("(null)");
        else
            Console::WriteLine("\"{0}\"", s);
    }
};

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();
    dinosaurs->Add("Pachycephalosaurus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("");
    dinosaurs->Add(nullptr);
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Deinonychus");
    Display(dinosaurs);

    Console::WriteLine("\nSort with generic Comparison<String^> delegate:");
    dinosaurs->Sort(
        gcnew Comparison<String^>(CompareDinosByLength));
    Display(dinosaurs);

}

/* This code example produces the following output:

"Pachycephalosaurus"
"Amargasaurus"
""
(null)
"Mamenchisaurus"
"Deinonychus"

Sort with generic Comparison<String^> delegate:

(null)
""
"Deinonychus"
"Amargasaurus"
"Mamenchisaurus"
"Pachycephalosaurus"
 */
using System;
using System.Collections.Generic;

public class Example
{
    private static int CompareDinosByLength(string x, string y)
    {
        if (x == null)
        {
            if (y == null)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == null)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x.Length.CompareTo(y.Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x.CompareTo(y);
                }
            }
        }
    }

    public static void Main()
    {
        List<string> dinosaurs = new List<string>();
        dinosaurs.Add("Pachycephalosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("");
        dinosaurs.Add(null);
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");
        Display(dinosaurs);

        Console.WriteLine("\nSort with generic Comparison<string> delegate:");
        dinosaurs.Sort(CompareDinosByLength);
        Display(dinosaurs);

    }

    private static void Display(List<string> list)
    {
        Console.WriteLine();
        foreach( string s in list )
        {
            if (s == null)
                Console.WriteLine("(null)");
            else
                Console.WriteLine("\"{0}\"", s);
        }
    }
}

/* This code example produces the following output:

"Pachycephalosaurus"
"Amargasaurus"
""
(null)
"Mamenchisaurus"
"Deinonychus"

Sort with generic Comparison<string> delegate:

(null)
""
"Deinonychus"
"Amargasaurus"
"Mamenchisaurus"
"Pachycephalosaurus"
 */
Imports System.Collections.Generic

Public Class Example

    Private Shared Function CompareDinosByLength( _
        ByVal x As String, ByVal y As String) As Integer

        If x Is Nothing Then
            If y Is Nothing Then 
                ' If x is Nothing and y is Nothing, they're
                ' equal. 
                Return 0
            Else
                ' If x is Nothing and y is not Nothing, y
                ' is greater. 
                Return -1
            End If
        Else
            ' If x is not Nothing...
            '
            If y Is Nothing Then
                ' ...and y is Nothing, x is greater.
                Return 1
            Else
                ' ...and y is not Nothing, compare the 
                ' lengths of the two strings.
                '
                Dim retval As Integer = _
                    x.Length.CompareTo(y.Length)

                If retval <> 0 Then 
                    ' If the strings are not of equal length,
                    ' the longer string is greater.
                    '
                    Return retval
                Else
                    ' If the strings are of equal length,
                    ' sort them with ordinary string comparison.
                    '
                    Return x.CompareTo(y)
                End If
            End If
        End If

    End Function

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)
        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("")
        dinosaurs.Add(Nothing)
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Deinonychus")
        Display(dinosaurs)

        Console.WriteLine(vbLf & "Sort with generic Comparison(Of String) delegate:")
        dinosaurs.Sort(AddressOf CompareDinosByLength)
        Display(dinosaurs)

    End Sub

    Private Shared Sub Display(ByVal lis As List(Of String))
        Console.WriteLine()
        For Each s As String In lis
            If s Is Nothing Then
                Console.WriteLine("(Nothing)")
            Else
                Console.WriteLine("""{0}""", s)
            End If
        Next
    End Sub
End Class

' This code example produces the following output:
'
'"Pachycephalosaurus"
'"Amargasaurus"
'""
'(Nothing)
'"Mamenchisaurus"
'"Deinonychus"
'
'Sort with generic Comparison(Of String) delegate:
'
'(Nothing)
'""
'"Deinonychus"
'"Amargasaurus"
'"Mamenchisaurus"
'"Pachycephalosaurus"

注釈

comparison が指定されている場合、List<T> の要素は、デリゲートによって表されるメソッドを使用して並べ替えられます。If comparison is provided, the elements of the List<T> are sorted using the method represented by the delegate.

comparisonnull場合は、ArgumentNullException がスローされます。If comparison is null, an ArgumentNullException is thrown.

このメソッドは Array.Sortを使用します。これにより、次のように introspective sort が適用されます。This method uses Array.Sort, which applies the introspective sort as follows:

  • パーティションサイズが16要素以下の場合は、挿入並べ替えアルゴリズムが使用されます。If the partition size is less than or equal to 16 elements, it uses an insertion sort algorithm

  • パーティションの数が2つのログn( nは入力配列の範囲) を超えている場合、 heapsortアルゴリズムが使用されます。If the number of partitions exceeds 2 log n, where n is the range of the input array, it uses a Heapsort algorithm.

  • それ以外の場合は、クイックソートアルゴリズムを使用します。Otherwise, it uses a Quicksort algorithm.

この実装は、不安定な並べ替えを実行します。つまり、2つの要素が等しい場合、その順序は保持されない可能性があります。This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. これに対して、安定した並べ替えでは、等しい要素の順序が保持されます。In contrast, a stable sort preserves the order of elements that are equal.

平均して、このメソッドは O (n log n) 操作です。ここで、 nCountです。最悪のケースでは、O (n2) 操作です。On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n2) operation.

こちらもご覧ください

Sort(Int32, Int32, IComparer<T>)

指定した比較子を使用して、List<T> 内の要素の範囲内の要素を並べ替えます。Sorts the elements in a range of elements in List<T> using the specified comparer.

public:
 void Sort(int index, int count, System::Collections::Generic::IComparer<T> ^ comparer);
public void Sort (int index, int count, System.Collections.Generic.IComparer<T> comparer);
member this.Sort : int * int * System.Collections.Generic.IComparer<'T> -> unit
Public Sub Sort (index As Integer, count As Integer, comparer As IComparer(Of T))

パラメーター

index
Int32

並べ替える範囲の開始位置を示す 0 から始まるインデックス。The zero-based starting index of the range to sort.

count
Int32

並べ替える範囲の長さ。The length of the range to sort.

comparer
IComparer<T>

要素を比較する場合に使用する IComparer<T> 実装。または、既定の比較子 Default を使用する場合は nullThe IComparer<T> implementation to use when comparing elements, or null to use the default comparer Default.

例外

index が 0 未満です。index is less than 0.

- または --or- count が 0 未満です。count is less than 0.

index および countList<T> において有効な範囲を指定していません。index and count do not specify a valid range in the List<T>.

- または --or- comparer の実装により、並べ替え中にエラーが発生しました。The implementation of comparer caused an error during the sort. たとえば、項目をそれ自体と比較する場合、comparer は 0 を返さない可能性があります。For example, comparer might not return 0 when comparing an item with itself.

comparernull で、既定の比較関数 DefaultIComparable<T> ジェネリック インターフェイスまたは T 型の IComparable インターフェイスの実装を見つけることができません。comparer is null, and the default comparer Default cannot find implementation of the IComparable<T> generic interface or the IComparable interface for type T.

次の例は、Sort(Int32, Int32, IComparer<T>) メソッドのオーバーロードと、BinarySearch(Int32, Int32, T, IComparer<T>) メソッドのオーバーロードを示しています。The following example demonstrates the Sort(Int32, Int32, IComparer<T>) method overload and the BinarySearch(Int32, Int32, T, IComparer<T>) method overload.

この例では、DinoCompare という名前の文字列の代替比較子を定義しています。これC++は、IComparer<string> (IComparer(Of String) Visual Basic では IComparer<String^>、Visual) ジェネリックインターフェイスに実装されています。The example defines an alternative comparer for strings named DinoCompare, which implements the IComparer<string> (IComparer(Of String) in Visual Basic, IComparer<String^> in Visual C++) generic interface. 比較子は次のように機能します。まず、比較対照値が nullに対してテストされ、null 参照が null 以外の値として処理されます。The comparer works as follows: First, the comparands are tested for null, and a null reference is treated as less than a non-null. 次に、文字列の長さが比較され、長い方の文字列が大きいと見なされます。Second, the string lengths are compared, and the longer string is deemed to be greater. 3番目の長さが等しい場合は、通常の文字列比較が使用されます。Third, if the lengths are equal, ordinary string comparison is used.

文字列の List<T> が作成され、5つの herbivorous 恐竜と3つの carnivorous 恐竜の名前が設定されます。A List<T> of strings is created and populated with the names of five herbivorous dinosaurs and three carnivorous dinosaurs. 2つのグループのそれぞれで、名前は特定の並べ替え順序ではありません。Within each of the two groups, the names are not in any particular sort order. 一覧が表示され、herbivores の範囲が代替比較子を使用して並べ替えられ、一覧が再び表示されます。The list is displayed, the range of herbivores is sorted using the alternate comparer, and the list is displayed again.

次に、BinarySearch(Int32, Int32, T, IComparer<T>) メソッドのオーバーロードを使用して、"Brachiosaurus" の herbivores の範囲だけを検索します。The BinarySearch(Int32, Int32, T, IComparer<T>) method overload is then used to search only the range of herbivores for "Brachiosaurus". 文字列が見つかりません。ビットごとの補数 (とのC#場合は ~ 演算子C++、とビジュアルの場合は-1 Visual Basic) は、BinarySearch(Int32, Int32, T, IComparer<T>)メソッドによって返された負の数値のXor、新しい文字列を挿入するためのインデックスとして使用されます。The string is not found, and the bitwise complement (the ~ operator in C# and Visual C++, Xor -1 in Visual Basic) of the negative number returned by the BinarySearch(Int32, Int32, T, IComparer<T>) method is used as an index for inserting the new string.

using namespace System;
using namespace System::Collections::Generic;

public ref class DinoComparer: IComparer<String^>
{
public:
    virtual int Compare(String^ x, String^ y)
    {
        if (x == nullptr)
        {
            if (y == nullptr)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == nullptr)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x->Length.CompareTo(y->Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x->CompareTo(y);
                }
            }
        }
    }
};

void Display(List<String^>^ list)
{
    Console::WriteLine();
    for each(String^ s in list)
    {
        Console::WriteLine(s);
    }
};

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();

    dinosaurs->Add("Pachycephalosaurus");
    dinosaurs->Add("Parasauralophus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("Galimimus");
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Deinonychus");
    dinosaurs->Add("Oviraptor");
    dinosaurs->Add("Tyrannosaurus");

    int herbivores = 5;
    Display(dinosaurs);

    DinoComparer^ dc = gcnew DinoComparer();

    Console::WriteLine("\nSort a range with the alternate comparer:");
    dinosaurs->Sort(0, herbivores, dc);
    Display(dinosaurs);

    Console::WriteLine("\nBinarySearch a range and Insert \"{0}\":",
            "Brachiosaurus");

    int index = dinosaurs->BinarySearch(0, herbivores, "Brachiosaurus", dc);

    if (index < 0)
    {
        dinosaurs->Insert(~index, "Brachiosaurus");
        herbivores++;
    }

    Display(dinosaurs);
}

/* This code example produces the following output:

Pachycephalosaurus
Parasauralophus
Amargasaurus
Galimimus
Mamenchisaurus
Deinonychus
Oviraptor
Tyrannosaurus

Sort a range with the alternate comparer:

Galimimus
Amargasaurus
Mamenchisaurus
Parasauralophus
Pachycephalosaurus
Deinonychus
Oviraptor
Tyrannosaurus

BinarySearch a range and Insert "Brachiosaurus":

Galimimus
Amargasaurus
Brachiosaurus
Mamenchisaurus
Parasauralophus
Pachycephalosaurus
Deinonychus
Oviraptor
Tyrannosaurus
 */
using System;
using System.Collections.Generic;

public class DinoComparer: IComparer<string>
{
    public int Compare(string x, string y)
    {
        if (x == null)
        {
            if (y == null)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == null)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x.Length.CompareTo(y.Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x.CompareTo(y);
                }
            }
        }
    }
}

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();

        dinosaurs.Add("Pachycephalosaurus");
        dinosaurs.Add("Parasauralophus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Galimimus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");
        dinosaurs.Add("Oviraptor");
        dinosaurs.Add("Tyrannosaurus");

        int herbivores = 5;
        Display(dinosaurs);

        DinoComparer dc = new DinoComparer();

        Console.WriteLine("\nSort a range with the alternate comparer:");
        dinosaurs.Sort(0, herbivores, dc);
        Display(dinosaurs);

        Console.WriteLine("\nBinarySearch a range and Insert \"{0}\":",
            "Brachiosaurus");

        int index = dinosaurs.BinarySearch(0, herbivores, "Brachiosaurus", dc);

        if (index < 0)
        {
            dinosaurs.Insert(~index, "Brachiosaurus");
            herbivores++;
        }

        Display(dinosaurs);
    }

    private static void Display(List<string> list)
    {
        Console.WriteLine();
        foreach( string s in list )
        {
            Console.WriteLine(s);
        }
    }
}

/* This code example produces the following output:

Pachycephalosaurus
Parasauralophus
Amargasaurus
Galimimus
Mamenchisaurus
Deinonychus
Oviraptor
Tyrannosaurus

Sort a range with the alternate comparer:

Galimimus
Amargasaurus
Mamenchisaurus
Parasauralophus
Pachycephalosaurus
Deinonychus
Oviraptor
Tyrannosaurus

BinarySearch a range and Insert "Brachiosaurus":

Galimimus
Amargasaurus
Brachiosaurus
Mamenchisaurus
Parasauralophus
Pachycephalosaurus
Deinonychus
Oviraptor
Tyrannosaurus
 */
Imports System.Collections.Generic

Public Class DinoComparer
    Implements IComparer(Of String)

    Public Function Compare(ByVal x As String, _
        ByVal y As String) As Integer _
        Implements IComparer(Of String).Compare

        If x Is Nothing Then
            If y Is Nothing Then 
                ' If x is Nothing and y is Nothing, they're
                ' equal. 
                Return 0
            Else
                ' If x is Nothing and y is not Nothing, y
                ' is greater. 
                Return -1
            End If
        Else
            ' If x is not Nothing...
            '
            If y Is Nothing Then
                ' ...and y is Nothing, x is greater.
                Return 1
            Else
                ' ...and y is not Nothing, compare the 
                ' lengths of the two strings.
                '
                Dim retval As Integer = _
                    x.Length.CompareTo(y.Length)

                If retval <> 0 Then 
                    ' If the strings are not of equal length,
                    ' the longer string is greater.
                    '
                    Return retval
                Else
                    ' If the strings are of equal length,
                    ' sort them with ordinary string comparison.
                    '
                    Return x.CompareTo(y)
                End If
            End If
        End If
    End Function
End Class

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Parasauralophus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Galimimus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Deinonychus")
        dinosaurs.Add("Oviraptor")
        dinosaurs.Add("Tyrannosaurus")

        Dim herbivores As Integer = 5
        Display(dinosaurs)

        Dim dc As New DinoComparer

        Console.WriteLine(vbLf & _
            "Sort a range with the alternate comparer:")
        dinosaurs.Sort(0, herbivores, dc)
        Display(dinosaurs)

        Console.WriteLine(vbLf & _
            "BinarySearch a range and Insert ""{0}"":", _
            "Brachiosaurus")

        Dim index As Integer = _
            dinosaurs.BinarySearch(0, herbivores, "Brachiosaurus", dc)

        If index < 0 Then
            index = index Xor -1
            dinosaurs.Insert(index, "Brachiosaurus")
            herbivores += 1
        End If

        Display(dinosaurs)

    End Sub

    Private Shared Sub Display(ByVal lis As List(Of String))
        Console.WriteLine()
        For Each s As String In lis
            Console.WriteLine(s)
        Next
    End Sub
End Class

' This code example produces the following output:
'
'Pachycephalosaurus
'Parasauralophus
'Amargasaurus
'Galimimus
'Mamenchisaurus
'Deinonychus
'Oviraptor
'Tyrannosaurus
'
'Sort a range with the alternate comparer:
'
'Galimimus
'Amargasaurus
'Mamenchisaurus
'Parasauralophus
'Pachycephalosaurus
'Deinonychus
'Oviraptor
'Tyrannosaurus
'
'BinarySearch a range and Insert "Brachiosaurus":
'
'Galimimus
'Amargasaurus
'Brachiosaurus
'Mamenchisaurus
'Parasauralophus
'Pachycephalosaurus
'Deinonychus
'Oviraptor
'Tyrannosaurus

注釈

comparer が指定されている場合、List<T> の要素は、指定された IComparer<T> 実装を使用して並べ替えられます。If comparer is provided, the elements of the List<T> are sorted using the specified IComparer<T> implementation.

comparernull場合、既定の比較 Comparer<T>.Default 子は、型 TIComparable<T> ジェネリックインターフェイスを実装し、その実装を使用できる場合にその実装を使用するかどうかをチェックします。If comparer is null, the default comparer Comparer<T>.Default checks whether type T implements the IComparable<T> generic interface and uses that implementation, if available. それ以外の場合は、Comparer<T>.DefaultTIComparable インターフェイスを実装しているかどうかを確認します。If not, Comparer<T>.Default checks whether type T implements the IComparable interface. T がどちらのインターフェイスも実装していない場合、Comparer<T>.DefaultInvalidOperationExceptionをスローします。If type T does not implement either interface, Comparer<T>.Default throws an InvalidOperationException.

このメソッドは Array.Sortを使用します。これにより、次のように introspective sort が適用されます。This method uses Array.Sort, which applies the introspective sort as follows:

  • パーティションサイズが16要素以下の場合は、挿入並べ替えアルゴリズムが使用されます。If the partition size is less than or equal to 16 elements, it uses an insertion sort algorithm

  • パーティションの数が2つのログn( nは入力配列の範囲) を超えている場合、 heapsortアルゴリズムが使用されます。If the number of partitions exceeds 2 log n, where n is the range of the input array, it uses a Heapsort algorithm.

  • それ以外の場合は、クイックソートアルゴリズムを使用します。Otherwise, it uses a Quicksort algorithm.

この実装は、不安定な並べ替えを実行します。つまり、2つの要素が等しい場合、その順序は保持されない可能性があります。This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. これに対して、安定した並べ替えでは、等しい要素の順序が保持されます。In contrast, a stable sort preserves the order of elements that are equal.

平均して、このメソッドは O (n log n) 操作です。ここで、 nCountです。最悪のケースでは、O (n2) 操作です。On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n2) operation.

こちらもご覧ください

Sort()

既定の比較子を使用して、List<T> 全体内の要素を並べ替えます。Sorts the elements in the entire List<T> using the default comparer.

public:
 void Sort();
public void Sort ();
member this.Sort : unit -> unit
Public Sub Sort ()

例外

既定の比較関数 Default は、IComparable<T> ジェネリック インターフェイスまたは T 型の IComparable インターフェイスの実装を見つけることができません。The default comparer Default cannot find an implementation of the IComparable<T> generic interface or the IComparable interface for type T.

次の例では、List<String> オブジェクトにいくつかの名前を追加し、並べ替えられていない順序で一覧を表示し、Sort メソッドを呼び出して、並べ替えられたリストを表示します。The following example adds some names to a List<String> object, displays the list in unsorted order, calls the Sort method, and then displays the sorted list.

String[] names = { "Samuel", "Dakota", "Koani", "Saya", "Vanya", "Jody",
                   "Yiska", "Yuma", "Jody", "Nikita" };
var nameList = new List<String>();
nameList.AddRange(names);
Console.WriteLine("List in unsorted order: ");
foreach (var name in nameList)
   Console.Write("   {0}", name);

Console.WriteLine(Environment.NewLine);

nameList.Sort();
Console.WriteLine("List in sorted order: ");
foreach (var name in nameList)
   Console.Write("   {0}", name);

Console.WriteLine();

// The example displays the following output:
//    List in unsorted order:
//       Samuel   Dakota   Koani   Saya   Vanya   Jody   Yiska   Yuma   Jody   Nikita
//
//    List in sorted order:
//       Dakota   Jody   Jody   Koani   Nikita   Samuel   Saya   Vanya   Yiska   Yuma
Imports System.Collections.Generic

Module Example
   Public Sub Main()
      Dim names() As String = { "Samuel", "Dakota", "Koani", "Saya",
                                "Vanya", "Jody", "Yiska", "Yuma", 
                                "Jody", "Nikita" }
      Dim nameList As New List(Of String)()
      nameList.AddRange(names)
      Console.WriteLine("List in unsorted order: ")
      For Each name In nameList
         Console.Write("   {0}", name)
      Next
      Console.WriteLine(vbCrLf)

      nameList.Sort()
      Console.WriteLine("List in sorted order: ")
      For Each name In nameList
         Console.Write("   {0}", name)
      Next
      Console.WriteLine()
    End Sub
End Module
' The example displays the following output:
'    List in unsorted order:
'       Samuel   Dakota   Koani   Saya   Vanya   Jody   Yiska   Yuma   Jody   Nikita
'
'    List in sorted order:
'       Dakota   Jody   Jody   Koani   Nikita   Samuel   Saya   Vanya   Yiska   Yuma

次のコードは、単純なビジネスオブジェクトでの Sort()Sort(Comparison<T>) メソッドのオーバーロードを示しています。The following code demonstrates the Sort() and Sort(Comparison<T>) method overloads on a simple business object. Sort() メソッドを呼び出すと、パーツ型の既定の比較子が使用され、Sort(Comparison<T>) メソッドは匿名メソッドを使用して実装されます。Calling the Sort() method results in the use of the default comparer for the Part type, and the Sort(Comparison<T>) method is implemented by using an anonymous method.

using System;
using System.Collections.Generic;
// Simple business object. A PartId is used to identify the type of part 
// but the part name can change. 
public class Part : IEquatable<Part> , IComparable<Part>
{
    public string PartName { get; set; }

    public int PartId { get; set; }

    public override string ToString()
    {
        return "ID: " + PartId + "   Name: " + PartName;
    }
    public override bool Equals(object obj)
    {
        if (obj == null) return false;
        Part objAsPart = obj as Part;
        if (objAsPart == null) return false;
        else return Equals(objAsPart);
    }
    public int SortByNameAscending(string name1, string name2)
    {
        
        return name1.CompareTo(name2);
    }

    // Default comparer for Part type.
    public int CompareTo(Part comparePart)
    {
          // A null value means that this object is greater.
        if (comparePart == null)
            return 1;
            
        else
            return this.PartId.CompareTo(comparePart.PartId);
    }
    public override int GetHashCode()
    {
        return PartId;
    }
    public bool Equals(Part other)
    {
        if (other == null) return false;
        return (this.PartId.Equals(other.PartId));
    }
    // Should also override == and != operators.

}
public class Example
{
    public static void Main()
    {
        // Create a list of parts.
        List<Part> parts = new List<Part>();

        // Add parts to the list.
        parts.Add(new Part() { PartName = "regular seat", PartId = 1434 });
        parts.Add(new Part() { PartName= "crank arm", PartId = 1234 });
        parts.Add(new Part() { PartName = "shift lever", PartId = 1634 }); ;
        // Name intentionally left null.
        parts.Add(new Part() {  PartId = 1334 });
        parts.Add(new Part() { PartName = "banana seat", PartId = 1444 });
        parts.Add(new Part() { PartName = "cassette", PartId = 1534 });
       

        // Write out the parts in the list. This will call the overridden 
        // ToString method in the Part class.
        Console.WriteLine("\nBefore sort:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }


        // Call Sort on the list. This will use the 
        // default comparer, which is the Compare method 
        // implemented on Part.
        parts.Sort();


        Console.WriteLine("\nAfter sort by part number:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }
       
        // This shows calling the Sort(Comparison(T) overload using 
        // an anonymous method for the Comparison delegate. 
        // This method treats null as the lesser of two values.
        parts.Sort(delegate(Part x, Part y)
        {
            if (x.PartName == null && y.PartName == null) return 0;
            else if (x.PartName == null) return -1;
            else if (y.PartName == null) return 1;
            else return x.PartName.CompareTo(y.PartName);
        });

        Console.WriteLine("\nAfter sort by name:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }
       
        /*
       
            Before sort:
        ID: 1434   Name: regular seat
        ID: 1234   Name: crank arm
        ID: 1634   Name: shift lever
        ID: 1334   Name:
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette

        After sort by part number:
        ID: 1234   Name: crank arm
        ID: 1334   Name:
        ID: 1434   Name: regular seat
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette
        ID: 1634   Name: shift lever

        After sort by name:
        ID: 1334   Name:
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette
        ID: 1234   Name: crank arm
        ID: 1434   Name: regular seat
        ID: 1634   Name: shift lever

         */

    }
}
Imports System.Collections.Generic

' Simple business object. A PartId is used to identify the type of part 
' but the part name can change. 
Public Class Part
    Implements IEquatable(Of Part)
    Implements IComparable(Of Part)
    Public Property PartName() As String
        Get
            Return m_PartName
        End Get
        Set(value As String)
            m_PartName = Value
        End Set
    End Property
    Private m_PartName As String

    Public Property PartId() As Integer
        Get
            Return m_PartId
        End Get
        Set(value As Integer)
            m_PartId = Value
        End Set
    End Property
    Private m_PartId As Integer

    Public Overrides Function ToString() As String
        Return "ID: " & PartId & "   Name: " & PartName
    End Function

    Public Overrides Function Equals(obj As Object) As Boolean
        If obj Is Nothing Then
            Return False
        End If
        Dim objAsPart As Part = TryCast(obj, Part)
        If objAsPart Is Nothing Then
            Return False
        Else
            Return Equals(objAsPart)
        End If
    End Function

    Public Function SortByNameAscending(name1 As String, name2 As String) As Integer

        Return name1.CompareTo(name2)
    End Function

    ' Default comparer for Part.
    Public Function CompareTo(comparePart As Part) As Integer _
            Implements IComparable(Of ListSortVB.Part).CompareTo
        ' A null value means that this object is greater.
        If comparePart Is Nothing Then
            Return 1
        Else

            Return Me.PartId.CompareTo(comparePart.PartId)
        End If
    End Function
    Public Overrides Function GetHashCode() As Integer
        Return PartId
    End Function
    Public Overloads Function Equals(other As Part) As Boolean Implements IEquatable(Of ListSortVB.Part).Equals
        If other Is Nothing Then
            Return False
        End If
        Return (Me.PartId.Equals(other.PartId))
    End Function
    ' Should also override == and != operators.

End Class
Public Class Example
    Public Shared Sub Main()
        ' Create a list of parts.
        Dim parts As New List(Of Part)()

        ' Add parts to the list.
        parts.Add(New Part() With { _
             .PartName = "regular seat", _
             .PartId = 1434 _
        })
        parts.Add(New Part() With { _
             .PartName = "crank arm", _
             .PartId = 1234 _
        })
        parts.Add(New Part() With { _
             .PartName = "shift lever", _
             .PartId = 1634 _
        })


        ' Name intentionally left null.
        parts.Add(New Part() With { _
             .PartId = 1334 _
        })
        parts.Add(New Part() With { _
             .PartName = "banana seat", _
             .PartId = 1444 _
        })
        parts.Add(New Part() With { _
             .PartName = "cassette", _
             .PartId = 1534 _
        })


        ' Write out the parts in the list. This will call the overridden 
        ' ToString method in the Part class.
        Console.WriteLine(vbLf & "Before sort:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next


        ' Call Sort on the list. This will use the 
        ' default comparer, which is the Compare method 
        ' implemented on Part.
        parts.Sort()


        Console.WriteLine(vbLf & "After sort by part number:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next

        ' This shows calling the Sort(Comparison(T) overload using 
        ' an anonymous delegate method. 
        ' This method treats null as the lesser of two values.
        parts.Sort(Function(x As Part, y As Part)
                             If x.PartName Is Nothing AndAlso y.PartName Is Nothing Then
                                 Return 0
                             ElseIf x.PartName Is Nothing Then
                                 Return -1
                             ElseIf y.PartName Is Nothing Then
                                 Return 1
                             Else
                                 Return x.PartName.CompareTo(y.PartName)
                             End If
                         End Function)
        

        Console.WriteLine(vbLf & "After sort by name:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next

        '
        '        
        '            Before sort:
        '            ID: 1434   Name: regular seat
        '            ID: 1234   Name: crank arm
        '            ID: 1634   Name: shift lever
        '            ID: 1334   Name:
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '
        '            After sort by part number:
        '            ID: 1234   Name: crank arm
        '            ID: 1334   Name:
        '            ID: 1434   Name: regular seat
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '            ID: 1634   Name: shift lever
        '
        '            After sort by name:
        '            ID: 1334   Name:
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '            ID: 1234   Name: crank arm
        '            ID: 1434   Name: regular seat
        '            ID: 1634   Name: shift lever

    End Sub
End Class

次の例は、Sort() メソッドのオーバーロードと、BinarySearch(T) メソッドのオーバーロードを示しています。The following example demonstrates the Sort() method overload and the BinarySearch(T) method overload. 文字列の List<T> が作成され、特定の順序ではなく4つの文字列が設定されます。A List<T> of strings is created and populated with four strings, in no particular order. 一覧が表示され、並べ替えられて、もう一度表示されます。The list is displayed, sorted, and displayed again.

次に、BinarySearch(T) メソッドのオーバーロードを使用して、リストに含まれていない2つの文字列を検索し、Insert メソッドを使用してそれらの文字列を挿入します。The BinarySearch(T) method overload is then used to search for two strings that are not in the list, and the Insert method is used to insert them. 文字列がリストに含まれていないため、BinarySearch メソッドの戻り値は、各ケースで負の値になります。The return value of the BinarySearch method is negative in each case, because the strings are not in the list. ビットごとの補数 (およびでC#は ~ 演算子) C++を取得すると、この負の数値のXor-1 Visual Basic) によって、検索文字列よりも大きいリスト内の最初の要素のインデックスが生成されます。この位置にを挿入すると、並べ替え順序。Taking the bitwise complement (the ~ operator in C# and Visual C++, Xor -1 in Visual Basic) of this negative number produces the index of the first element in the list that is larger than the search string, and inserting at this location preserves the sort order. 2番目の検索文字列がリスト内のどの要素よりも大きいため、挿入位置がリストの末尾にあります。The second search string is larger than any element in the list, so the insertion position is at the end of the list.

using namespace System;
using namespace System::Collections::Generic;

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();

    dinosaurs->Add("Pachycephalosaurus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Deinonychus");

    Console::WriteLine();
    for each(String^ dinosaur in dinosaurs)
    {
        Console::WriteLine(dinosaur);
    }

    Console::WriteLine("\nSort");
    dinosaurs->Sort();

    Console::WriteLine();
    for each(String^ dinosaur in dinosaurs)
    {
        Console::WriteLine(dinosaur);
    }

    Console::WriteLine("\nBinarySearch and Insert \"Coelophysis\":");
    int index = dinosaurs->BinarySearch("Coelophysis");
    if (index < 0)
    {
        dinosaurs->Insert(~index, "Coelophysis");
    }

    Console::WriteLine();
    for each(String^ dinosaur in dinosaurs)
    {
        Console::WriteLine(dinosaur);
    }

    Console::WriteLine("\nBinarySearch and Insert \"Tyrannosaurus\":");
    index = dinosaurs->BinarySearch("Tyrannosaurus");
    if (index < 0)
    {
        dinosaurs->Insert(~index, "Tyrannosaurus");
    }

    Console::WriteLine();
    for each(String^ dinosaur in dinosaurs)
    {
        Console::WriteLine(dinosaur);
    }
}

/* This code example produces the following output:

Pachycephalosaurus
Amargasaurus
Mamenchisaurus
Deinonychus

Sort

Amargasaurus
Deinonychus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Coelophysis":

Amargasaurus
Coelophysis
Deinonychus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Tyrannosaurus":

Amargasaurus
Coelophysis
Deinonychus
Mamenchisaurus
Pachycephalosaurus
Tyrannosaurus
 */
using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();

        dinosaurs.Add("Pachycephalosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\nSort");
        dinosaurs.Sort();

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\nBinarySearch and Insert \"Coelophysis\":");
        int index = dinosaurs.BinarySearch("Coelophysis");
        if (index < 0)
        {
            dinosaurs.Insert(~index, "Coelophysis");
        }

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\nBinarySearch and Insert \"Tyrannosaurus\":");
        index = dinosaurs.BinarySearch("Tyrannosaurus");
        if (index < 0)
        {
            dinosaurs.Insert(~index, "Tyrannosaurus");
        }

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }
    }
}

/* This code example produces the following output:

Pachycephalosaurus
Amargasaurus
Mamenchisaurus
Deinonychus

Sort

Amargasaurus
Deinonychus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Coelophysis":

Amargasaurus
Coelophysis
Deinonychus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Tyrannosaurus":

Amargasaurus
Coelophysis
Deinonychus
Mamenchisaurus
Pachycephalosaurus
Tyrannosaurus
 */
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Deinonychus")

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & "Sort")
        dinosaurs.Sort

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "BinarySearch and Insert ""Coelophysis"":")
        Dim index As Integer = dinosaurs.BinarySearch("Coelophysis")
        If index < 0 Then
            index = index Xor -1
            dinosaurs.Insert(index, "Coelophysis")
        End If

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "BinarySearch and Insert ""Tyrannosaurus"":")
        index = dinosaurs.BinarySearch("Tyrannosaurus")
        If index < 0 Then
            index = index Xor -1
            dinosaurs.Insert(index, "Tyrannosaurus")
        End If

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

    End Sub
End Class

' This code example produces the following output:
'
'Pachycephalosaurus
'Amargasaurus
'Mamenchisaurus
'Deinonychus
'
'Sort
'
'Amargasaurus
'Deinonychus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Coelophysis":
'
'Amargasaurus
'Coelophysis
'Deinonychus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Tyrannosaurus":
'
'Amargasaurus
'Coelophysis
'Deinonychus
'Mamenchisaurus
'Pachycephalosaurus
'Tyrannosaurus

注釈

このメソッドは、型 T の既定の比較子 Comparer<T>.Default を使用して、リスト要素の順序を決定します。This method uses the default comparer Comparer<T>.Default for type T to determine the order of list elements. Comparer<T>.Default プロパティは、型 TIComparable<T> ジェネリックインターフェイスを実装し、その実装を使用するかどうかを確認します (使用可能な場合)。The Comparer<T>.Default property checks whether type T implements the IComparable<T> generic interface and uses that implementation, if available. それ以外の場合は、Comparer<T>.DefaultTIComparable インターフェイスを実装しているかどうかを確認します。If not, Comparer<T>.Default checks whether type T implements the IComparable interface. T がどちらのインターフェイスも実装していない場合、Comparer<T>.DefaultInvalidOperationExceptionをスローします。If type T does not implement either interface, Comparer<T>.Default throws an InvalidOperationException.

このメソッドは Array.Sort メソッドを使用し、次のように introspective sort を適用します。This method uses the Array.Sort method, which applies the introspective sort as follows:

  • パーティションサイズが16要素以下の場合は、挿入並べ替えアルゴリズムが使用されます。If the partition size is less than or equal to 16 elements, it uses an insertion sort algorithm.

  • パーティションの数が2つのログn( nは入力配列の範囲) を超えている場合、heapsort アルゴリズムが使用されます。If the number of partitions exceeds 2 log n, where n is the range of the input array, it uses a Heapsort algorithm.

  • それ以外の場合は、クイックソートアルゴリズムを使用します。Otherwise, it uses a Quicksort algorithm.

この実装は、不安定な並べ替えを実行します。つまり、2つの要素が等しい場合、その順序は保持されない可能性があります。This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. これに対して、安定した並べ替えでは、等しい要素の順序が保持されます。In contrast, a stable sort preserves the order of elements that are equal.

平均して、このメソッドは O (n log n) 操作です。ここで、 nCountです。最悪のケースでは、O (n2) 操作です。On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n2) operation.

こちらもご覧ください

Sort(IComparer<T>)

指定した比較子を使用して、List<T> 全体内の要素を並べ替えます。Sorts the elements in the entire List<T> using the specified comparer.

public:
 void Sort(System::Collections::Generic::IComparer<T> ^ comparer);
public void Sort (System.Collections.Generic.IComparer<T> comparer);
member this.Sort : System.Collections.Generic.IComparer<'T> -> unit
Public Sub Sort (comparer As IComparer(Of T))

パラメーター

comparer
IComparer<T>

要素を比較する場合に使用する IComparer<T> 実装。または、既定の比較子 Default を使用する場合は nullThe IComparer<T> implementation to use when comparing elements, or null to use the default comparer Default.

例外

comparernull で、既定の比較関数 DefaultIComparable<T> ジェネリック インターフェイスまたは T 型の IComparable インターフェイスの実装を見つけることができません。comparer is null, and the default comparer Default cannot find implementation of the IComparable<T> generic interface or the IComparable interface for type T.

comparer の実装により、並べ替え中にエラーが発生しました。The implementation of comparer caused an error during the sort. たとえば、comparer は、項目をそれ自体と比較したときに 0 を返さなかった可能性があります。For example, comparer might not return 0 when comparing an item with itself.

次の例は、Sort(IComparer<T>) メソッドのオーバーロードと、BinarySearch(T, IComparer<T>) メソッドのオーバーロードを示しています。The following example demonstrates the Sort(IComparer<T>) method overload and the BinarySearch(T, IComparer<T>) method overload.

この例では、DinoCompare という名前の文字列の代替比較子を定義しています。これC++は、IComparer<string> (IComparer(Of String) Visual Basic では IComparer<String^>、Visual) ジェネリックインターフェイスに実装されています。The example defines an alternative comparer for strings named DinoCompare, which implements the IComparer<string> (IComparer(Of String) in Visual Basic, IComparer<String^> in Visual C++) generic interface. 比較子は次のように機能します。まず、比較対照値が nullに対してテストされ、null 参照が null 以外の値として処理されます。The comparer works as follows: First, the comparands are tested for null, and a null reference is treated as less than a non-null. 次に、文字列の長さが比較され、長い方の文字列が大きいと見なされます。Second, the string lengths are compared, and the longer string is deemed to be greater. 3番目の長さが等しい場合は、通常の文字列比較が使用されます。Third, if the lengths are equal, ordinary string comparison is used.

文字列の List<T> が作成され、特定の順序ではなく4つの文字列が設定されます。A List<T> of strings is created and populated with four strings, in no particular order. 一覧が表示され、代替比較子を使用して並べ替えられて、もう一度表示されます。The list is displayed, sorted using the alternate comparer, and displayed again.

次に、BinarySearch(T, IComparer<T>) メソッドのオーバーロードを使用して、リストに含まれていない複数の文字列を検索し、代替比較子を使用します。The BinarySearch(T, IComparer<T>) method overload is then used to search for several strings that are not in the list, employing the alternate comparer. Insert メソッドは、文字列を挿入するために使用されます。The Insert method is used to insert the strings. これら2つのメソッドは、SearchAndInsertという名前の関数に配置され、ビットごとの補数 (and C#XorビジュアルC++では ~ 演算子、はBinarySearch(T, IComparer<T>)によって返された負の数の Visual Basic) を使用して、挿入された ti のインデックスとして使用します。新しい文字列を作成します。These two methods are located in the function named SearchAndInsert, along with code to take the bitwise complement (the ~ operator in C# and Visual C++, Xor -1 in Visual Basic) of the negative number returned by BinarySearch(T, IComparer<T>) and use it as an index for inserting the new string.

using namespace System;
using namespace System::Collections::Generic;

public ref class DinoComparer: IComparer<String^>
{
public:
    virtual int Compare(String^ x, String^ y)
    {
        if (x == nullptr)
        {
            if (y == nullptr)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == nullptr)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x->Length.CompareTo(y->Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x->CompareTo(y);
                }
            }
        }
    }
};

void SearchAndInsert(List<String^>^ list, String^ insert, 
    DinoComparer^ dc)
{
    Console::WriteLine("\nBinarySearch and Insert \"{0}\":", insert);

    int index = list->BinarySearch(insert, dc);

    if (index < 0)
    {
        list->Insert(~index, insert);
    }
};

void Display(List<String^>^ list)
{
    Console::WriteLine();
    for each(String^ s in list)
    {
        Console::WriteLine(s);
    }
};

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();
    dinosaurs->Add("Pachycephalosaurus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Deinonychus");
    Display(dinosaurs);

    DinoComparer^ dc = gcnew DinoComparer();

    Console::WriteLine("\nSort with alternate comparer:");
    dinosaurs->Sort(dc);
    Display(dinosaurs);

    SearchAndInsert(dinosaurs, "Coelophysis", dc);
    Display(dinosaurs);

    SearchAndInsert(dinosaurs, "Oviraptor", dc);
    Display(dinosaurs);

    SearchAndInsert(dinosaurs, "Tyrannosaur", dc);
    Display(dinosaurs);

    SearchAndInsert(dinosaurs, nullptr, dc);
    Display(dinosaurs);
}

/* This code example produces the following output:

Pachycephalosaurus
Amargasaurus
Mamenchisaurus
Deinonychus

Sort with alternate comparer:

Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Coelophysis":

Coelophysis
Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Oviraptor":

Oviraptor
Coelophysis
Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Tyrannosaur":

Oviraptor
Coelophysis
Deinonychus
Tyrannosaur
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "":


Oviraptor
Coelophysis
Deinonychus
Tyrannosaur
Amargasaurus
Mamenchisaurus
Pachycephalosaurus
 */
using System;
using System.Collections.Generic;

public class DinoComparer: IComparer<string>
{
    public int Compare(string x, string y)
    {
        if (x == null)
        {
            if (y == null)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == null)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x.Length.CompareTo(y.Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x.CompareTo(y);
                }
            }
        }
    }
}

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();
        dinosaurs.Add("Pachycephalosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");
        Display(dinosaurs);

        DinoComparer dc = new DinoComparer();

        Console.WriteLine("\nSort with alternate comparer:");
        dinosaurs.Sort(dc);
        Display(dinosaurs);

        SearchAndInsert(dinosaurs, "Coelophysis", dc);
        Display(dinosaurs);

        SearchAndInsert(dinosaurs, "Oviraptor", dc);
        Display(dinosaurs);

        SearchAndInsert(dinosaurs, "Tyrannosaur", dc);
        Display(dinosaurs);

        SearchAndInsert(dinosaurs, null, dc);
        Display(dinosaurs);
    }

    private static void SearchAndInsert(List<string> list, 
        string insert, DinoComparer dc)
    {
        Console.WriteLine("\nBinarySearch and Insert \"{0}\":", insert);

        int index = list.BinarySearch(insert, dc);

        if (index < 0)
        {
            list.Insert(~index, insert);
        }
    }

    private static void Display(List<string> list)
    {
        Console.WriteLine();
        foreach( string s in list )
        {
            Console.WriteLine(s);
        }
    }
}

/* This code example produces the following output:

Pachycephalosaurus
Amargasaurus
Mamenchisaurus
Deinonychus

Sort with alternate comparer:

Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Coelophysis":

Coelophysis
Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Oviraptor":

Oviraptor
Coelophysis
Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Tyrannosaur":

Oviraptor
Coelophysis
Deinonychus
Tyrannosaur
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "":


Oviraptor
Coelophysis
Deinonychus
Tyrannosaur
Amargasaurus
Mamenchisaurus
Pachycephalosaurus
 */
Imports System.Collections.Generic

Public Class DinoComparer
    Implements IComparer(Of String)

    Public Function Compare(ByVal x As String, _
        ByVal y As String) As Integer _
        Implements IComparer(Of String).Compare

        If x Is Nothing Then
            If y Is Nothing Then 
                ' If x is Nothing and y is Nothing, they're
                ' equal. 
                Return 0
            Else
                ' If x is Nothing and y is not Nothing, y
                ' is greater. 
                Return -1
            End If
        Else
            ' If x is not Nothing...
            '
            If y Is Nothing Then
                ' ...and y is Nothing, x is greater.
                Return 1
            Else
                ' ...and y is not Nothing, compare the 
                ' lengths of the two strings.
                '
                Dim retval As Integer = _
                    x.Length.CompareTo(y.Length)

                If retval <> 0 Then 
                    ' If the strings are not of equal length,
                    ' the longer string is greater.
                    '
                    Return retval
                Else
                    ' If the strings are of equal length,
                    ' sort them with ordinary string comparison.
                    '
                    Return x.CompareTo(y)
                End If
            End If
        End If
    End Function
End Class

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)
        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Deinonychus")
        Display(dinosaurs)

        Dim dc As New DinoComparer

        Console.WriteLine(vbLf & "Sort with alternate comparer:")
        dinosaurs.Sort(dc)
        Display(dinosaurs)

        SearchAndInsert(dinosaurs, "Coelophysis", dc)
        Display(dinosaurs)

        SearchAndInsert(dinosaurs, "Oviraptor", dc)
        Display(dinosaurs)

        SearchAndInsert(dinosaurs, "Tyrannosaur", dc)
        Display(dinosaurs)

        SearchAndInsert(dinosaurs, Nothing, dc)
        Display(dinosaurs)
    End Sub

    Private Shared Sub SearchAndInsert( _
        ByVal lis As List(Of String), _
        ByVal insert As String, ByVal dc As DinoComparer)

        Console.WriteLine(vbLf & _
            "BinarySearch and Insert ""{0}"":", insert)

        Dim index As Integer = lis.BinarySearch(insert, dc)

        If index < 0 Then
            index = index Xor -1
            lis.Insert(index, insert)
        End If
    End Sub

    Private Shared Sub Display(ByVal lis As List(Of String))
        Console.WriteLine()
        For Each s As String In lis
            Console.WriteLine(s)
        Next
    End Sub
End Class

' This code example produces the following output:
'
'Pachycephalosaurus
'Amargasaurus
'Mamenchisaurus
'Deinonychus
'
'Sort with alternate comparer:
'
'Deinonychus
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Coelophysis":
'
'Coelophysis
'Deinonychus
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Oviraptor":
'
'Oviraptor
'Coelophysis
'Deinonychus
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Tyrannosaur":
'
'Oviraptor
'Coelophysis
'Deinonychus
'Tyrannosaur
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "":
'
'
'Oviraptor
'Coelophysis
'Deinonychus
'Tyrannosaur
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus

注釈

comparer が指定されている場合、List<T> の要素は、指定された IComparer<T> 実装を使用して並べ替えられます。If comparer is provided, the elements of the List<T> are sorted using the specified IComparer<T> implementation.

comparernull場合、既定の比較 Comparer<T>.Default 子は、型 TIComparable<T> ジェネリックインターフェイスを実装し、その実装を使用できる場合にその実装を使用するかどうかをチェックします。If comparer is null, the default comparer Comparer<T>.Default checks whether type T implements the IComparable<T> generic interface and uses that implementation, if available. それ以外の場合は、Comparer<T>.DefaultTIComparable インターフェイスを実装しているかどうかを確認します。If not, Comparer<T>.Default checks whether type T implements the IComparable interface. T がどちらのインターフェイスも実装していない場合、Comparer<T>.DefaultInvalidOperationExceptionをスローします。If type T does not implement either interface, Comparer<T>.Default throws an InvalidOperationException.

このメソッドは Array.Sort メソッドを使用し、次のように introspective sort を適用します。This method uses the Array.Sort method, which applies the introspective sort as follows:

  • パーティションサイズが16要素以下の場合は、挿入並べ替えアルゴリズムが使用されます。If the partition size is less than or equal to 16 elements, it uses an insertion sort algorithm.

  • パーティションの数が2つのログn( nは入力配列の範囲) を超えている場合、heapsort アルゴリズムが使用されます。If the number of partitions exceeds 2 log n, where n is the range of the input array, it uses a Heapsort algorithm.

  • それ以外の場合は、クイックソートアルゴリズムを使用します。Otherwise, it uses a Quicksort algorithm.

この実装は、不安定な並べ替えを実行します。つまり、2つの要素が等しい場合、その順序は保持されない可能性があります。This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. これに対して、安定した並べ替えでは、等しい要素の順序が保持されます。In contrast, a stable sort preserves the order of elements that are equal.

平均して、このメソッドは O (n log n) 操作です。ここで、 nCountです。最悪のケースでは、O (n2) 操作です。On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n2) operation.

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