ArrayList.RemoveAt(Int32) Methode

public:
 virtual void RemoveAt(int index);

public virtual void RemoveAt(int index);

abstract member RemoveAt : int -> unit
override this.RemoveAt : int -> unit

Public Overridable Sub RemoveAt (index As Integer)

Parameters

Implementeringen

Uitzonderingen

Voorbeelden

In het volgende codevoorbeeld ziet u hoe u elementen uit de ArrayList.

using System;
using System.Collections;
public class SamplesArrayList  {

   public static void Main()  {

      // Creates and initializes a new ArrayList.
      ArrayList myAL = new ArrayList();
      myAL.Add( "The" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );
      myAL.Add( "jumps" );
      myAL.Add( "over" );
      myAL.Add( "the" );
      myAL.Add( "lazy" );
      myAL.Add( "dog" );

      // Displays the ArrayList.
      Console.WriteLine( "The ArrayList initially contains the following:" );
      PrintValues( myAL );

      // Removes the element containing "lazy".
      myAL.Remove( "lazy" );

      // Displays the current state of the ArrayList.
      Console.WriteLine( "After removing \"lazy\":" );
      PrintValues( myAL );

      // Removes the element at index 5.
      myAL.RemoveAt( 5 );

      // Displays the current state of the ArrayList.
      Console.WriteLine( "After removing the element at index 5:" );
      PrintValues( myAL );

      // Removes three elements starting at index 4.
      myAL.RemoveRange( 4, 3 );

      // Displays the current state of the ArrayList.
      Console.WriteLine( "After removing three elements starting at index 4:" );
      PrintValues( myAL );
   }

   public static void PrintValues( IEnumerable myList )  {
      foreach ( Object obj in myList )
         Console.Write( "   {0}", obj );
      Console.WriteLine();
   }
}
/*
This code produces the following output.

The ArrayList initially contains the following:
   The   quick   brown   fox   jumps   over   the   lazy   dog
After removing "lazy":
   The   quick   brown   fox   jumps   over   the   dog
After removing the element at index 5:
   The   quick   brown   fox   jumps   the   dog
After removing three elements starting at index 4:
   The   quick   brown   fox
*/

Imports System.Collections

Public Class SamplesArrayList    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new ArrayList.
        Dim myAL As New ArrayList()
        myAL.Add("The")
        myAL.Add("quick")
        myAL.Add("brown")
        myAL.Add("fox")
        myAL.Add("jumps")
        myAL.Add("over")
        myAL.Add("the")
        myAL.Add("lazy")
        myAL.Add("dog")
        
        ' Displays the ArrayList.
        Console.WriteLine("The ArrayList initially contains the following:")
        PrintValues(myAL)
        
        ' Removes the element containing "lazy".
        myAL.Remove("lazy")
        
        ' Displays the current state of the ArrayList.
        Console.WriteLine("After removing ""lazy"":")
        PrintValues(myAL)
        
        ' Removes the element at index 5.
        myAL.RemoveAt(5)
        
        ' Displays the current state of the ArrayList.
        Console.WriteLine("After removing the element at index 5:")
        PrintValues(myAL)
        
        ' Removes three elements starting at index 4.
        myAL.RemoveRange(4, 3)
        
        ' Displays the current state of the ArrayList.
        Console.WriteLine("After removing three elements starting at index 4:")
        PrintValues(myAL)
    End Sub
    
    Public Shared Sub PrintValues(myList As IEnumerable)
        Dim obj As [Object]
        For Each obj In  myList
            Console.Write("   {0}", obj)
        Next obj
        Console.WriteLine()
    End Sub

End Class


' This code produces the following output.
' 
' The ArrayList initially contains the following:
'    The   quick   brown   fox   jumps   over   the   lazy   dog
' After removing "lazy":
'    The   quick   brown   fox   jumps   over   the   dog
' After removing the element at index 5:
'    The   quick   brown   fox   jumps   the   dog
' After removing three elements starting at index 4:
'    The   quick   brown   fox

Opmerkingen

Nadat het element is verwijderd, wordt de grootte van de verzameling aangepast en wordt de waarde van de Count eigenschap met één verkleind.

In verzamelingen van aaneengesloten elementen, zoals lijsten, worden de elementen die volgen op het verwijderde element omhoog verplaatst om de onbezette plek te bezetten. Als de verzameling is geïndexeerd, worden de indexen van de verplaatste elementen ook bijgewerkt. Dit gedrag is niet van toepassing op verzamelingen waarin elementen conceptueel zijn gegroepeerd in buckets, zoals een hash-tabel.

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

Zie ook

• Remove(Object)
• RemoveRange(Int32, Int32)
• Add(Object)
• Insert(Int32, Object)