ArrayList.RemoveAt(Int32) ArrayList.RemoveAt(Int32) ArrayList.RemoveAt(Int32) ArrayList.RemoveAt(Int32) Method

Definição

Remove o elemento no índice especificado do ArrayList.Removes the element at the specified index of the ArrayList.

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)

Parâmetros

index
Int32 Int32 Int32 Int32

O índice de base zero do elemento a ser removido.The zero-based index of the element to remove.

Implementações

Exceções

index é menor que zero.index is less than zero.

- ou --or- index é igual a ou maior que Count.index is equal to or greater than Count.

O ArrayList é somente leitura.The ArrayList is read-only.

- ou --or- O ArrayList tem um tamanho fixo.The ArrayList has a fixed size.

Exemplos

O exemplo de código a seguir mostra como remover elementos do ArrayList.The following code example shows how to remove elements from the ArrayList.

using namespace System;
using namespace System::Collections;
void PrintValues( IEnumerable^ myList );
int main()
{
   
   // Creates and initializes a new ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "The" );
   myAL->Add( "quick" );
   myAL->Add( "brown" );
   myAL->Add( "fox" );
   myAL->Add( "jumps" );
   myAL->Add( "over" );
   myAL->Add( "the" );
   myAL->Add( "lazy" );
   myAL->Add( "dog" );
   
   // Displays the 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 );
}

void PrintValues( IEnumerable^ myList )
{
   IEnumerator^ myEnum = myList->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ obj = safe_cast<Object^>(myEnum->Current);
      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
 */
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

Comentários

Depois que o elemento é removido, o tamanho da coleção é ajustado e o valor da propriedade Count é reduzido em um.After the element is removed, the size of the collection is adjusted and the value of the Count property is decreased by one.

Em coleções de elementos contíguos, como listas, os elementos que seguem o elemento removido sobem para ocupar o ponto vazio.In collections of contiguous elements, such as lists, the elements that follow the removed element move up to occupy the vacated spot. Caso a coleção seja indexada, os índices dos elementos que são movidos também são atualizados.If the collection is indexed, the indexes of the elements that are moved are also updated. Este comportamento não se aplica às coleções em que elementos sejam agrupados conceitualmente em buckets, como uma tabela de hash.This behavior does not apply to collections where elements are conceptually grouped into buckets, such as a hash table.

Esse método é uma operação O(n), em que n é Count.This method is an O(n) operation, where n is Count.

Aplica-se a

Veja também