ArraySegment<T> 構造体

定義

generic <typename T>
public value class ArraySegment : System::Collections::Generic::ICollection<T>, System::Collections::Generic::IEnumerable<T>, System::Collections::Generic::IList<T>, System::Collections::Generic::IReadOnlyCollection<T>, System::Collections::Generic::IReadOnlyList<T>

generic <typename T>
public value class ArraySegment

public struct ArraySegment<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>

public readonly struct ArraySegment<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>

[System.Serializable]
public struct ArraySegment<T>

[System.Serializable]
public struct ArraySegment<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>

type ArraySegment<'T> = struct
    interface ICollection<'T>
    interface seq<'T>
    interface IEnumerable
    interface IList<'T>
    interface IReadOnlyCollection<'T>
    interface IReadOnlyList<'T>

[<System.Serializable>]
type ArraySegment<'T> = struct

[<System.Serializable>]
type ArraySegment<'T> = struct
    interface IList<'T>
    interface ICollection<'T>
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>
    interface seq<'T>
    interface IEnumerable

[<System.Serializable>]
type ArraySegment<'T> = struct
    interface IList<'T>
    interface ICollection<'T>
    interface seq<'T>
    interface IEnumerable
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>

type ArraySegment<'T> = struct
    interface IList<'T>
    interface ICollection<'T>
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>
    interface seq<'T>
    interface IEnumerable

Public Structure ArraySegment(Of T)
Implements ICollection(Of T), IEnumerable(Of T), IList(Of T), IReadOnlyCollection(Of T), IReadOnlyList(Of T)

Public Structure ArraySegment(Of T)

型パラメーター

継承

Object

ValueType

ArraySegment<T>

属性

SerializableAttribute

実装

ICollection<T> IEnumerable<T> IList<T> IReadOnlyCollection<T> IReadOnlyList<T> IEnumerable

例

次のコード例では、ArraySegment<T> 構造体をメソッドに渡します。

using namespace System;


namespace Sample
{
    public ref class SampleArray  
    {
    public:
        static void Work()  
        {

            // Create and initialize a new string array.
            array <String^>^ words = {"The", "quick", "brown",
                "fox", "jumps", "over", "the", "lazy", "dog"};

            // Display the initial contents of the array.
            Console::WriteLine("The first array segment"
                " (with all the array's elements) contains:");
            PrintIndexAndValues(words);

            // Define an array segment that contains the entire array.
            ArraySegment<String^> segment(words);
            
            // Display the contents of the ArraySegment.
            Console::WriteLine("The first array segment"
                " (with all the array's elements) contains:");
            PrintIndexAndValues(segment);

            // Define an array segment that contains the middle five 
            // values of the array.
            ArraySegment<String^> middle(words, 2, 5);
            
            // Display the contents of the ArraySegment.
            Console::WriteLine("The second array segment"
                " (with the middle five elements) contains:");
            PrintIndexAndValues(middle);

            // Modify the fourth element of the first array 
            // segment
            segment.Array[3] = "LION";

            // Display the contents of the second array segment 
            // middle. Note that the value of its second element 
            // also changed.
            Console::WriteLine("After the first array segment"
                " is modified,the second array segment"
                " now contains:");
            PrintIndexAndValues(middle);
            Console::ReadLine();
        }

        static void PrintIndexAndValues(ArraySegment<String^>^ segment)  
        {
            for (int i = segment->Offset; 
                i < (segment->Offset + segment->Count); i++)  
            {
                Console::WriteLine("   [{0}] : {1}", i,
                    segment->Array[i]);
            }
            Console::WriteLine();
        }

        static void PrintIndexAndValues(array<String^>^ words) 
        {
            for (int i = 0; i < words->Length; i++)  
            {
                Console::WriteLine("   [{0}] : {1}", i,
                    words[i]);
            }
            Console::WriteLine();
        }
    };
}

int main()
{
    Sample::SampleArray::Work();
    return 0; 
}


    /* 
    This code produces the following output.

    The original array initially contains:
    [0] : The
    [1] : quick
    [2] : brown
    [3] : fox
    [4] : jumps
    [5] : over
    [6] : the
    [7] : lazy
    [8] : dog

    The first array segment (with all the array's elements) contains:
    [0] : The
    [1] : quick
    [2] : brown
    [3] : fox
    [4] : jumps
    [5] : over
    [6] : the
    [7] : lazy
    [8] : dog

    The second array segment (with the middle five elements) contains:
    [2] : brown
    [3] : fox
    [4] : jumps
    [5] : over
    [6] : the

    After the first array segment is modified, the second array segment now contains:
    [2] : brown
    [3] : LION
    [4] : jumps
    [5] : over
    [6] : the

    */

using System;

public class SamplesArray  {

   public static void Main()  {

      // Create and initialize a new string array.
      String[] myArr = { "The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog" };

      // Display the initial contents of the array.
      Console.WriteLine( "The original array initially contains:" );
      PrintIndexAndValues( myArr );

      // Define an array segment that contains the entire array.
      ArraySegment<string> myArrSegAll = new ArraySegment<string>( myArr );

      // Display the contents of the ArraySegment.
      Console.WriteLine( "The first array segment (with all the array's elements) contains:" );
      PrintIndexAndValues( myArrSegAll );

      // Define an array segment that contains the middle five values of the array.
      ArraySegment<string> myArrSegMid = new ArraySegment<string>( myArr, 2, 5 );

      // Display the contents of the ArraySegment.
      Console.WriteLine( "The second array segment (with the middle five elements) contains:" );
      PrintIndexAndValues( myArrSegMid );

      // Modify the fourth element of the first array segment myArrSegAll.
      myArrSegAll.Array[3] = "LION";

      // Display the contents of the second array segment myArrSegMid.
      // Note that the value of its second element also changed.
      Console.WriteLine( "After the first array segment is modified, the second array segment now contains:" );
      PrintIndexAndValues( myArrSegMid );
   }

   public static void PrintIndexAndValues( ArraySegment<string> arrSeg )  {
      for ( int i = arrSeg.Offset; i < (arrSeg.Offset + arrSeg.Count); i++ )  {
         Console.WriteLine( "   [{0}] : {1}", i, arrSeg.Array[i] );
      }
      Console.WriteLine();
   }

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


/*
This code produces the following output.

The original array initially contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The first array segment (with all the array's elements) contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The second array segment (with the middle five elements) contains:
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the

After the first array segment is modified, the second array segment now contains:
   [2] : brown
   [3] : LION
   [4] : jumps
   [5] : over
   [6] : the

*/

open System

// Print functions.
let printIndexAndValues (myArr: string []) =
    for i = 0 to myArr.Length - 1 do
        printfn $"   [{i}] : {myArr[i]}"
    printfn ""

let printIndexAndValuesSeg (arrSeg: ArraySegment<string>) =
    for i = arrSeg.Offset to arrSeg.Offset + arrSeg.Count - 1 do
        printfn $"   [{i}] : {arrSeg.Array[i]}"
    printfn ""

// Create and initialize a new string array.
let myArr = [| "The"; "quick"; "brown"; "fox"; "jumps"; "over"; "the"; "lazy"; "dog" |]

// Display the initial contents of the array.
printfn "The original array initially contains:"
printIndexAndValues myArr

// Define an array segment that contains the entire array.
let myArrSegAll = ArraySegment<string>(myArr)

// Display the contents of the ArraySegment.
printfn "The first array segment (with all the array's elements) contains:"
printIndexAndValuesSeg myArrSegAll

// Define an array segment that contains the middle five values of the array.
let myArrSegMid = ArraySegment<string>(myArr, 2, 5)

// Display the contents of the ArraySegment.
printfn "The second array segment (with the middle five elements) contains:"
printIndexAndValuesSeg myArrSegMid

// Modify the fourth element of the first array segment myArrSegAll.
myArrSegAll.Array[3] <- "LION"

// Display the contents of the second array segment myArrSegMid.
// Note that the value of its second element also changed.
printfn "After the first array segment is modified, the second array segment now contains:"
printIndexAndValuesSeg myArrSegMid


(*
This code produces the following output.

The original array initially contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The first array segment (with all the array's elements) contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The second array segment (with the middle five elements) contains:
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the

After the first array segment is modified, the second array segment now contains:
   [2] : brown
   [3] : LION
   [4] : jumps
   [5] : over
   [6] : the

*)

Public Class SamplesArray

    Public Shared Sub Main()

        ' Create and initialize a new string array.
        Dim myArr As String() =  {"The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"}

        ' Display the initial contents of the array.
        Console.WriteLine("The original array initially contains:")
        PrintIndexAndValues(myArr)

        ' Define an array segment that contains the entire array.
        Dim myArrSegAll As New ArraySegment(Of String)(myArr)

        ' Display the contents of the ArraySegment.
        Console.WriteLine("The first array segment (with all the array's elements) contains:")
        PrintIndexAndValues(myArrSegAll)

        ' Define an array segment that contains the middle five values of the array.
        Dim myArrSegMid As New ArraySegment(Of String)(myArr, 2, 5)

        ' Display the contents of the ArraySegment.
        Console.WriteLine("The second array segment (with the middle five elements) contains:")
        PrintIndexAndValues(myArrSegMid)

        ' Modify the fourth element of the first array segment myArrSegAll.
        myArrSegAll.Array(3) = "LION"

        ' Display the contents of the second array segment myArrSegMid.
        ' Note that the value of its second element also changed.
        Console.WriteLine("After the first array segment is modified, the second array segment now contains:")
        PrintIndexAndValues(myArrSegMid)

    End Sub

    Public Shared Sub PrintIndexAndValues(arrSeg As ArraySegment(Of String))
        Dim i As Integer
        For i = arrSeg.Offset To (arrSeg.Offset + arrSeg.Count - 1)
            Console.WriteLine("   [{0}] : {1}", i, arrSeg.Array(i))
        Next i
        Console.WriteLine()
    End Sub

    Public Shared Sub PrintIndexAndValues(myArr as String())
        Dim i As Integer
        For i = 0 To (myArr.Length - 1)
            Console.WriteLine("   [{0}] : {1}", i, myArr(i))
        Next i
        Console.WriteLine()
    End Sub

End Class


'This code produces the following output.
'
'The original array initially contains:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'The first array segment (with all the array's elements) contains:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'The second array segment (with the middle five elements) contains:
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'
'After the first array segment is modified, the second array segment now contains:
'   [2] : brown
'   [3] : LION
'   [4] : jumps
'   [5] : over
'   [6] : the

注釈

ArraySegment<T> は、その配列内の要素の範囲を区切る配列のラッパーです。 複数の ArraySegment<T> インスタンスは、同じ元の配列を参照でき、重複する可能性があります。 元の配列は 1 次元でなければならず、0 から始まるインデックスが必要です。

ArraySegment<T> 構造体は、配列の要素が個別のセグメントで操作されるたびに便利です。 例えば：

• Copy などの比較的高価なメソッドを呼び出して配列の一部のコピーを渡すのではなく、配列の一部のみを表す ArraySegment<T> オブジェクトをメソッドに渡すことができます。

• マルチスレッド アプリでは、ArraySegment<T> 構造体を使用して、各スレッドが配列の一部でのみ動作するようにすることができます。

• タスク ベースの非同期操作では、ArraySegment<T> オブジェクトを使用して、各タスクが配列の個別のセグメントで動作することを確認できます。 次の例では、最大 10 個の要素を持つ個々のセグメントに配列を分割します。 セグメント内の各要素に、そのセグメント番号が乗算されます。 結果は、ArraySegment<T> クラスを使用してこの方法で要素を操作すると、基になる配列の値が変更されることを示しています。

  using System;
  using System.Collections.Generic;
  using System.Threading.Tasks;
  
  public class Example
  {
     private const int segmentSize = 10;
  
     public static async Task Main()
     {
        List<Task> tasks = new List<Task>();
  
        // Create array.
        int[] arr = new int[50];
        for (int ctr = 0; ctr <= arr.GetUpperBound(0); ctr++)
           arr[ctr] = ctr + 1;
  
        // Handle array in segments of 10.
        for (int ctr = 1; ctr <= Math.Ceiling(((double)arr.Length)/segmentSize); ctr++) {
           int multiplier = ctr;
           int elements = (multiplier - 1) * 10 + segmentSize > arr.Length ?
                           arr.Length - (multiplier - 1) * 10 : segmentSize;
           ArraySegment<int> segment = new ArraySegment<int>(arr, (ctr - 1) * 10, elements);
           tasks.Add(Task.Run( () => { IList<int> list = (IList<int>) segment;
                                       for (int index = 0; index < list.Count; index++)
                                          list[index] = list[index] * multiplier;
                                     } ));
        }
        try {
           await Task.WhenAll(tasks.ToArray());
           int elementsShown = 0;
           foreach (var value in arr) {
              Console.Write("{0,3} ", value);
              elementsShown++;
              if (elementsShown % 18 == 0)
                 Console.WriteLine();
           }
        }
        catch (AggregateException e) {
           Console.WriteLine("Errors occurred when working with the array:");
           foreach (var inner in e.InnerExceptions)
              Console.WriteLine("{0}: {1}", inner.GetType().Name, inner.Message);
        }
     }
  }
  // The example displays the following output:
  //      1   2   3   4   5   6   7   8   9  10  22  24  26  28  30  32  34  36
  //     38  40  63  66  69  72  75  78  81  84  87  90 124 128 132 136 140 144
  //    148 152 156 160 205 210 215 220 225 230 235 240 245 250
  

  open System
  open System.Threading.Tasks
  
  // Create array.
  let arr = Array.init 50 (fun i -> i + 1)
  
  // Handle array in segments of 10.
  let tasks =
      Array.chunkBySize 10 arr
      |> Array.mapi (fun m elements ->
          let mutable segment = ArraySegment<int>(arr, m * 10, elements.Length)
          task {
              for i = 0 to segment.Count - 1 do
                  segment[i] <- segment[i] * (m + 1)
          } :> Task)
  
  try
      Task.WhenAll(tasks).Wait()
      let mutable i = 0
  
      for value in arr do
          printf $"{value, 3} "
          i <- i + 1
          if i % 18 = 0 then printfn ""
  
  with :? AggregateException as e ->
      printfn "Errors occurred when working with the array:"
  
      for inner in e.InnerExceptions do
          printfn $"{inner.GetType().Name}: {inner.Message}"
  
  
  // The example displays the following output:
  //      1   2   3   4   5   6   7   8   9  10  22  24  26  28  30  32  34  36
  //     38  40  63  66  69  72  75  78  81  84  87  90 124 128 132 136 140 144
  //    148 152 156 160 205 210 215 220 225 230 235 240 245 250
  

  Imports System.Collections.Generic
  Imports System.Threading.Tasks
  
  Module Example
    Private Const SegmentSize As Integer = 10
    
     Public Sub Main()
        Dim tasks As New List(Of Task)
        
         ' Create array.
        Dim arr(49) As Integer
        For ctr As Integer = 0 To arr.GetUpperBound(0)
           arr(ctr) = ctr + 1
        Next
  
        ' Handle array in segments of 10.
        For ctr As Integer = 1 To CInt(Math.Ceiling(arr.Length / segmentSize))
           Dim multiplier As Integer = ctr
           Dim elements As Integer = If((multiplier - 1) * 10 + segmentSize > arr.Length,
                                        arr.Length - (multiplier - 1) * 10,
                                        segmentSize)
           Dim segment As New ArraySegment(Of Integer)(arr, (ctr - 1) * 10, elements)
           tasks.Add(Task.Run( Sub()
                                  Dim list As IList(Of Integer) = CType(segment, IList(Of Integer))
                                  For index As Integer = 0 To list.Count - 1
                                     list(index) = list(index) * multiplier
                                  Next
                               End Sub ))
        Next
        Try
           Task.WaitAll(tasks.ToArray())
           Dim elementsShown As Integer = 0
           For Each value In arr
              Console.Write("{0,3} ", value)
              elementsShown += 1
              If elementsShown Mod 18 = 0 Then Console.WriteLine()
           Next
        Catch e As AggregateException
           Console.WriteLine("Errors occurred when working with the array:")
           For Each inner As Exception In e.InnerExceptions
              Console.WriteLine("{0}: {1}", inner.GetType().Name, inner.Message)
           Next
        End Try
     End Sub
  End Module
  ' The example displays the following output:
  '         1   2   3   4   5   6   7   8   9  10  22  24  26  28  30  32  34  36
  '        38  40  63  66  69  72  75  78  81  84  87  90 124 128 132 136 140 144
  '       148 152 156 160 205 210 215 220 225 230 235 240 245 250
  

ただし、ArraySegment<T> 構造体を使用して配列を個別のセグメントに分割することはできますが、セグメントが互いに完全に独立しているわけではありません。 Array プロパティは、配列のコピーではなく、元の配列全体を返します。したがって、Array プロパティによって返される配列に加えられた変更は、元の配列に対して行われます。 これが望ましくない場合は、配列の一部を表す ArraySegment<T> オブジェクトではなく、配列のコピーに対して操作を実行する必要があります。

Equals メソッドと等値演算子と等値演算子と不等値演算子は、2 つの ArraySegment<T> オブジェクトを比較するときに参照の等価性をテストします。 2 つの ArraySegment<T> オブジェクトを等しいと見なすには、次のすべての条件を満たす必要があります。

• 同じ配列を参照します。

• 配列内の同じインデックスから始めます。

• 同じ数の要素を持つ。

ArraySegment<T> オブジェクト内のインデックスによって要素を取得する場合は、IList<T> オブジェクトにキャストして取得するか、IList<T>.Item[] プロパティを使用して変更する必要があります。 これは F# では必要ありません。 次の例では、文字列配列のセクションを区切る ArraySegment<T> オブジェクト内の要素を取得します。

using System;
using System.Collections.Generic;

public class Example
{
   public static void Main()
   {
      String[] names = { "Adam", "Bruce", "Charles", "Daniel",
                         "Ebenezer", "Francis", "Gilbert",
                         "Henry", "Irving", "John", "Karl",
                         "Lucian", "Michael" };
      var partNames = new ArraySegment<string>(names, 2, 5);

      // Cast the ArraySegment object to an IList<string> and enumerate it.
      var list = (IList<string>) partNames;
      for (int ctr = 0; ctr <= list.Count - 1; ctr++)
         Console.WriteLine(list[ctr]);
   }
}
// The example displays the following output:
//    Charles
//    Daniel
//    Ebenezer
//    Francis
//    Gilbert

open System

let names = 
    [| "Adam"; "Bruce"; "Charles"; "Daniel"
       "Ebenezer"; "Francis"; "Gilbert"
       "Henry"; "Irving"; "John"; "Karl"
       "Lucian"; "Michael" |]

let partNames = ArraySegment<string>(names, 2, 5)

// Enumerate over the ArraySegment object.
for part in partNames do 
    printfn $"{part}"

// The example displays the following output:
//    Charles
//    Daniel
//    Ebenezer
//    Francis
//    Gilbert

Imports System.Collections.Generic

Module Example
   Public Sub Main()
      Dim names() As String = { "Adam", "Bruce", "Charles", "Daniel", 
                                "Ebenezer", "Francis", "Gilbert", 
                                "Henry", "Irving", "John", "Karl",
                                "Lucian", "Michael" }
      Dim partNames As New ArraySegment(Of String)(names, 2, 5)
      
      ' Cast the ArraySegment object to an IList<String> and enumerate it.
      Dim list = CType(partNames, IList(Of String))
      For ctr As Integer = 0 To list.Count - 1
         Console.WriteLine(list(ctr))
      Next     
   End Sub
End Module
' The example displays the following output:
'    Charles
'    Daniel
'    Ebenezer
'    Francis
'    Gilbert

コンストラクター

プロパティ

メソッド

演算子

明示的なインターフェイスの実装

拡張メソッド

適用対象

こちらもご覧ください

• Array