Hashtable.Remove(Object) Hashtable.Remove(Object) Hashtable.Remove(Object) Hashtable.Remove(Object) Method

Definition

Removes the element with the specified key from the Hashtable.

public:
 virtual void Remove(System::Object ^ key);
public virtual void Remove (object key);
abstract member Remove : obj -> unit
override this.Remove : obj -> unit
Public Overridable Sub Remove (key As Object)

Parameters

key
Object Object Object Object

The key of the element to remove.

Implements

Exceptions

Examples

The following example shows how to remove elements from the Hashtable.

using namespace System;
using namespace System::Collections;
void PrintKeysAndValues( Hashtable^ myHT );
int main()
{
   
   // Creates and initializes a new Hashtable.
   Hashtable^ myHT = gcnew Hashtable;
   myHT->Add( "1a", "The" );
   myHT->Add( "1b", "quick" );
   myHT->Add( "1c", "brown" );
   myHT->Add( "2a", "fox" );
   myHT->Add( "2b", "jumps" );
   myHT->Add( "2c", "over" );
   myHT->Add( "3a", "the" );
   myHT->Add( "3b", "lazy" );
   myHT->Add( "3c", "dog" );
   
   // Displays the Hashtable.
   Console::WriteLine( "The Hashtable initially contains the following:" );
   PrintKeysAndValues( myHT );
   
   // Removes the element with the key "3b".
   myHT->Remove( "3b" );
   
   // Displays the current state of the Hashtable.
   Console::WriteLine( "After removing \"lazy\":" );
   PrintKeysAndValues( myHT );
}

void PrintKeysAndValues( Hashtable^ myHT )
{
   IEnumerator^ myEnum = myHT->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      DictionaryEntry de = *safe_cast<DictionaryEntry ^>(myEnum->Current);
      Console::WriteLine( "    {0}:    {1}", de.Key, de.Value );
   }

   Console::WriteLine();
}

/*
 This code produces the following output.
 
 The Hashtable initially contains the following:
     2c:    over
     3a:    the
     2b:    jumps
     3b:    lazy
     1b:    quick
     3c:    dog
     2a:    fox
     1c:    brown
     1a:    The

 After removing "lazy":
     2c:    over
     3a:    the
     2b:    jumps
     1b:    quick
     3c:    dog
     2a:    fox
     1c:    brown
     1a:    The

 */
using System;
using System.Collections;
public class SamplesHashtable  {

   public static void Main()  {

      // Creates and initializes a new Hashtable.
      Hashtable myHT = new Hashtable();
      myHT.Add( "1a", "The" );
      myHT.Add( "1b", "quick" );
      myHT.Add( "1c", "brown" );
      myHT.Add( "2a", "fox" );
      myHT.Add( "2b", "jumps" );
      myHT.Add( "2c", "over" );
      myHT.Add( "3a", "the" );
      myHT.Add( "3b", "lazy" );
      myHT.Add( "3c", "dog" );

      // Displays the Hashtable.
      Console.WriteLine( "The Hashtable initially contains the following:" );
      PrintKeysAndValues( myHT );

      // Removes the element with the key "3b".
      myHT.Remove( "3b" );

      // Displays the current state of the Hashtable.
      Console.WriteLine( "After removing \"lazy\":" );
      PrintKeysAndValues( myHT );
   }


   public static void PrintKeysAndValues( Hashtable myHT )  {
      foreach ( DictionaryEntry de in myHT )
         Console.WriteLine( "    {0}:    {1}", de.Key, de.Value );
      Console.WriteLine();
   }

}


/*
This code produces the following output.

The Hashtable initially contains the following:
    2c:    over
    3a:    the
    2b:    jumps
    3b:    lazy
    1b:    quick
    3c:    dog
    2a:    fox
    1c:    brown
    1a:    The

After removing "lazy":
    2c:    over
    3a:    the
    2b:    jumps
    1b:    quick
    3c:    dog
    2a:    fox
    1c:    brown
    1a:    The

*/
Imports System
Imports System.Collections
Imports Microsoft.VisualBasic

Public Class SamplesHashtable    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new Hashtable.
        Dim myHT As New Hashtable()
        myHT.Add("1a", "The")
        myHT.Add("1b", "quick")
        myHT.Add("1c", "brown")
        myHT.Add("2a", "fox")
        myHT.Add("2b", "jumps")
        myHT.Add("2c", "over")
        myHT.Add("3a", "the")
        myHT.Add("3b", "lazy")
        myHT.Add("3c", "dog")
        
        ' Displays the Hashtable.
        Console.WriteLine("The Hashtable initially contains the following:")
        PrintKeysAndValues(myHT)
        
        ' Removes the element with the key "3b".
        myHT.Remove("3b")
        
        ' Displays the current state of the Hashtable.
        Console.WriteLine("After removing ""lazy"":")
        PrintKeysAndValues(myHT)
    End Sub    
    
    
    Public Shared Sub PrintKeysAndValues(myHT As Hashtable)
        Dim de As DictionaryEntry
        For Each de In  myHT
            Console.WriteLine("    {0}:    {1}", de.Key, de.Value)
        Next de
        Console.WriteLine()
    End Sub
End Class


' This code produces the following output.
' 
'The Hashtable initially contains the following:
'    2c:    over
'    3a:    the
'    2b:    jumps
'    3b:    lazy
'    1b:    quick
'    3c:    dog
'    2a:    fox
'    1c:    brown
'    1a:    The
'
'After removing "lazy":
'    2c:    over
'    3a:    the
'    2b:    jumps
'    1b:    quick
'    3c:    dog
'    2a:    fox
'    1c:    brown
'    1a:    The

Remarks

If the Hashtable does not contain an element with the specified key, the Hashtable remains unchanged. No exception is thrown.

This method is an O(1) operation.

Applies to

See Also