Array.Resize<T>(T[], Int32) Methode

public:
generic <typename T>
 static void Resize(cli::array <T> ^ % array, int newSize);

public static void Resize<T>(ref T[] array, int newSize);

public static void Resize<T>(ref T[]? array, int newSize);

static member Resize : T[] * int -> unit

Public Shared Sub Resize(Of T) (ByRef array As T(), newSize As Integer)

Type parameters

Parameters

Uitzonderingen

Voorbeelden

In het volgende voorbeeld ziet u hoe het wijzigen van de grootte van invloed is op de matrix.

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 values of the array.
        Console.WriteLine(
            "The string array initially contains the following values:");
        PrintIndexAndValues(myArr);

        // Resize the array to a bigger size (five elements larger).
        Array.Resize(ref myArr, myArr.Length + 5);

        // Display the values of the array.
        Console.WriteLine("After resizing to a larger size, ");
        Console.WriteLine("the string array contains the following values:");
        PrintIndexAndValues(myArr);

        // Resize the array to a smaller size (four elements).
        Array.Resize(ref myArr, 4);

        // Display the values of the array.
        Console.WriteLine("After resizing to a smaller size, ");
        Console.WriteLine("the string array contains the following values:");
        PrintIndexAndValues(myArr);
    }

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

After resizing to a larger size,
the string array contains the following values:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog
   [9] :
   [10] :
   [11] :
   [12] :
   [13] :

After resizing to a smaller size,
the string array contains the following values:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox

*/

open System

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

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

// Display the values of the array.
printfn "The string array initially contains the following values:"
printIndexAndValues myArr

// Resize the array to a bigger size (five elements larger).
Array.Resize(&myArr, myArr.Length + 5)

// Display the values of the array.
printfn "After resizing to a larger size, "
printfn "the string array contains the following values:"
printIndexAndValues myArr

// Resize the array to a smaller size (four elements).
Array.Resize(&myArr, 4)

// Display the values of the array.
printfn "After resizing to a smaller size, "
printfn "the string array contains the following values:"
printIndexAndValues myArr


(*
This code produces the following output.

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

After resizing to a larger size,
the string array contains the following values:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog
   [9] :
   [10] :
   [11] :
   [12] :
   [13] :

After resizing to a smaller size,
the string array contains the following values:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox

*)

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 values of the array.
        Console.WriteLine( _
            "The string array initially contains the following values:")
        PrintIndexAndValues(myArr)

        ' Resize the array to a bigger size (five elements larger).
        Array.Resize(myArr, myArr.Length + 5)

        ' Display the values of the array.
        Console.WriteLine("After resizing to a larger size, ")
        Console.WriteLine("the string array contains the following values:")
        PrintIndexAndValues(myArr)

        ' Resize the array to a smaller size (four elements).
        Array.Resize(myArr, 4)

        ' Display the values of the array.
        Console.WriteLine("After resizing to a smaller size, ")
        Console.WriteLine("the string array contains the following values:")
        PrintIndexAndValues(myArr)

    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 string array initially contains the following values:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'After resizing to a larger size, 
'the string array contains the following values:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'   [9] :
'   [10] :
'   [11] :
'   [12] :
'   [13] :
'
'After resizing to a smaller size, 
'the string array contains the following values:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox

Opmerkingen

Deze methode wijst een nieuwe matrix toe met de opgegeven grootte, kopieert elementen van de oude matrix naar de nieuwe en vervangt vervolgens de oude matrix door de nieuwe. array moet een eendimensionale matrix zijn.

Als array dat het is null, maakt deze methode een nieuwe matrix met de opgegeven grootte.

Als newSize deze groter is dan de Length oude matrix, wordt een nieuwe matrix toegewezen en worden alle elementen gekopieerd van de oude matrix naar de nieuwe matrix. Als newSize deze kleiner is dan de Length oude matrix, wordt een nieuwe matrix toegewezen en worden elementen gekopieerd van de oude matrix naar de nieuwe totdat de nieuwe wordt opgevuld. De rest van de elementen in de oude matrix worden genegeerd. Als newSize deze gelijk is aan de Length oude matrix, doet deze methode niets.

Deze methode is een O(n)-bewerking, waarbij n .newSize

De Resize methode wijzigt alleen de grootte van een eendimensionale matrix. De Array klasse bevat geen methode voor het wijzigen van het formaat van multidimensionale matrices. Hiervoor moet u uw eigen code opgeven of een methode voor speciaal doel aanroepen in een bibliotheek van derden. De volgende code illustreert één mogelijke implementatie voor een methode waarmee de grootte van een matrix van n dimensies wordt aangepast.

using System;

public class Example
{
   public static void Main()
   {
      int[,] arr = new int[10,2];
      for (int n1 = 0; n1 <= arr.GetUpperBound(0); n1++) {
         arr[n1, 0] = n1;
         arr[n1, 1] = n1 * 2;
      }

      // Make a 2-D array larger in the first dimension.
      arr = (int[,]) ResizeArray(arr, new int[] { 12, 2} );
      for (int ctr = 0; ctr <= arr.GetUpperBound(0); ctr++)
         Console.WriteLine("{0}: {1}, {2}", ctr, arr[ctr, 0], arr[ctr, 1]);
      Console.WriteLine();

      // Make a 2-D array smaller in the first dimension.
      arr = (int[,]) ResizeArray(arr, new int[] { 2, 2} );
      for (int ctr = 0; ctr <= arr.GetUpperBound(0); ctr++)
         Console.WriteLine("{0}: {1}, {2}", ctr, arr[ctr, 0], arr[ctr, 1]);
   }

   private static Array ResizeArray(Array arr, int[] newSizes)
   {
      if (newSizes.Length != arr.Rank)
         throw new ArgumentException("arr must have the same number of dimensions " +
                                     "as there are elements in newSizes", "newSizes");

      var temp = Array.CreateInstance(arr.GetType().GetElementType(), newSizes);
      int length = arr.Length <= temp.Length ? arr.Length : temp.Length;
      Array.ConstrainedCopy(arr, 0, temp, 0, length);
      return temp;
   }
}
// The example displays the following output:
//       0: 0, 0
//       1: 1, 2
//       2: 2, 4
//       3: 3, 6
//       4: 4, 8
//       5: 5, 10
//       6: 6, 12
//       7: 7, 14
//       8: 8, 16
//       9: 9, 18
//       10: 0, 0
//       11: 0, 0
//
//       0: 0, 0
//       1: 1, 2

open System

let resizeArray (arr: Array) (newSizes: int []) =
    if newSizes.Length <> arr.Rank then
        invalidArg "newSizes" "arr must have the same number of dimensions as there are elements in newSizes"
    let temp = Array.CreateInstance(arr.GetType().GetElementType(), newSizes)
    let length = min arr.Length temp.Length
    Array.ConstrainedCopy(arr, 0, temp, 0, length)
    temp

[<EntryPoint>]
let main _ =
    let arr = Array2D.init 10 2 (fun x y -> if y = 0 then x else x * 2)

    // Make a 2-D array larger in the first dimension.
    let arr = resizeArray arr [| 12; 2 |]
    for i = 0 to arr.GetUpperBound 0 do
        printfn $"{i}: {arr.GetValue(i, 0)}, {arr.GetValue(i, 1)}"
    printfn ""

    // Make a 2-D array smaller in the first dimension.
    let arr = resizeArray arr [| 2; 2|]
    for i = 0 to arr.GetUpperBound 0 do
        printfn $"{i}: {arr.GetValue(i, 0)}, {arr.GetValue(i, 1)}"
    0

// The example displays the following output:
//       0: 0, 0
//       1: 1, 2
//       2: 2, 4
//       3: 3, 6
//       4: 4, 8
//       5: 5, 10
//       6: 6, 12
//       7: 7, 14
//       8: 8, 16
//       9: 9, 18
//       10: 0, 0
//       11: 0, 0
//
//       0: 0, 0
//       1: 1, 2

Module Example
   Public Sub Main()
      Dim arr(9, 1) As Integer
      For n1 As Integer = 0 To arr.GetUpperBound(0)
         arr(n1, 0) = n1
         arr(n1, 1) = n1 * 2
      Next 

      ' Make a 2-D array larger in the first dimension.
      arr = CType(ResizeArray(arr, { 12, 2} ), Integer(,))
      For ctr = 0 To arr.GetUpperBound(0)
         Console.WriteLine("{0}: {1}, {2}", ctr, arr(ctr, 0), arr(ctr, 1))
      Next
      Console.WriteLine()
      
      ' Make a 2-D array smaller in the first dimension.
      arr = CType(ResizeArray(arr, { 2, 2} ), Integer(,))
      For ctr = 0 To arr.GetUpperBound(0)
         Console.WriteLine("{0}: {1}, {2}", ctr, arr(ctr, 0), arr(ctr, 1))
      Next
   End Sub

   Private Function ResizeArray(arr As Array, newSizes() As Integer) As Array
      If newSizes.Length <> arr.Rank Then
         Throw New ArgumentException("arr must have the same number of dimensions " +
                                     "as there are elements in newSizes", "newSizes") 
      End If 

      Dim temp As Array = Array.CreateInstance(arr.GetType().GetElementType(), newSizes)
      Dim length As Integer = If(arr.Length <= temp.Length, arr.Length, temp.Length )
      Array.ConstrainedCopy(arr, 0, temp, 0, length)
      Return temp
   End Function
End Module
' The example displays the following output:
'       0: 0, 0
'       1: 1, 2
'       2: 2, 4
'       3: 3, 6
'       4: 4, 8
'       5: 5, 10
'       6: 6, 12
'       7: 7, 14
'       8: 8, 16
'       9: 9, 18
'       10: 0, 0
'       11: 0, 0
'       
'       0: 0, 0
'       1: 1, 2