SortedList.RemoveAt(Int32) Method

Definition

Namespace:

System.Collections

Assembly:

System.Collections.NonGeneric.dll

Source:

SortedList.cs

Removes the element at the specified index of a SortedList object.

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

index

Int32

The zero-based index of the element to remove.

Exceptions

ArgumentOutOfRangeException

index is outside the range of valid indexes for the SortedList object.

NotSupportedException

The SortedList is read-only.

-or-

The SortedList has a fixed size.

Examples

The following code example shows how to remove elements from a SortedList object.

#using <system.dll>

using namespace System;
using namespace System::Collections;
void PrintKeysAndValues( SortedList^ myList )
{
   Console::WriteLine( "\t-KEY-\t-VALUE-" );
   for ( int i = 0; i < myList->Count; i++ )
   {
      Console::WriteLine( "\t{0}:\t{1}", myList->GetKey( i ), myList->GetByIndex( i ) );

   }
   Console::WriteLine();
}

int main()
{
   
   // Creates and initializes a new SortedList.
   SortedList^ mySL = gcnew SortedList;
   mySL->Add( "3c", "dog" );
   mySL->Add( "2c", "over" );
   mySL->Add( "1c", "brown" );
   mySL->Add( "1a", "The" );
   mySL->Add( "1b", "quick" );
   mySL->Add( "3a", "the" );
   mySL->Add( "3b", "lazy" );
   mySL->Add( "2a", "fox" );
   mySL->Add( "2b", "jumps" );
   
   // Displays the SortedList.
   Console::WriteLine( "The SortedList initially contains the following:" );
   PrintKeysAndValues( mySL );
   
   // Removes the element with the key "3b".
   mySL->Remove( "3b" );
   
   // Displays the current state of the SortedList.
   Console::WriteLine( "After removing \"lazy\":" );
   PrintKeysAndValues( mySL );
   
   // Removes the element at index 5.
   mySL->RemoveAt( 5 );
   
   // Displays the current state of the SortedList.
   Console::WriteLine( "After removing the element at index 5:" );
   PrintKeysAndValues( mySL );
}

/*
This code produces the following output.

The SortedList initially contains the following:
        -KEY-   -VALUE-
        1a:     The
        1b:     quick
        1c:     brown
        2a:     fox
        2b:     jumps
        2c:     over
        3a:     the
        3b:     lazy
        3c:     dog

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

After removing the element at index 5:
        -KEY-   -VALUE-
        1a:     The
        1b:     quick
        1c:     brown
        2a:     fox
        2b:     jumps
        3a:     the
        3c:     dog
*/

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

   public static void Main()  {

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

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

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

      // Displays the current state of the SortedList.
      Console.WriteLine( "After removing \"lazy\":" );
      PrintKeysAndValues( mySL );

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

      // Displays the current state of the SortedList.
      Console.WriteLine( "After removing the element at index 5:" );
      PrintKeysAndValues( mySL );
   }

   public static void PrintKeysAndValues( SortedList myList )  {
      Console.WriteLine( "\t-KEY-\t-VALUE-" );
      for ( int i = 0; i < myList.Count; i++ )  {
         Console.WriteLine( "\t{0}:\t{1}", myList.GetKey(i), myList.GetByIndex(i) );
      }
      Console.WriteLine();
   }
}
/*
This code produces the following output.

The SortedList initially contains the following:
    -KEY-    -VALUE-
    1a:    The
    1b:    quick
    1c:    brown
    2a:    fox
    2b:    jumps
    2c:    over
    3a:    the
    3b:    lazy
    3c:    dog

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

After removing the element at index 5:
    -KEY-    -VALUE-
    1a:    The
    1b:    quick
    1c:    brown
    2a:    fox
    2b:    jumps
    3a:    the
    3c:    dog
*/

Imports System.Collections

Public Class SamplesSortedList    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new SortedList.
        Dim mySL As New SortedList()
        mySL.Add("3c", "dog")
        mySL.Add("2c", "over")
        mySL.Add("1c", "brown")
        mySL.Add("1a", "The")
        mySL.Add("1b", "quick")
        mySL.Add("3a", "the")
        mySL.Add("3b", "lazy")
        mySL.Add("2a", "fox")
        mySL.Add("2b", "jumps")
        
        ' Displays the SortedList.
        Console.WriteLine("The SortedList initially contains the following:")
        PrintKeysAndValues(mySL)
        
        ' Removes the element with the key "3b".
        mySL.Remove("3b")
        
        ' Displays the current state of the SortedList.
        Console.WriteLine("After removing ""lazy"":")
        PrintKeysAndValues(mySL)
        
        ' Removes the element at index 5.
        mySL.RemoveAt(5)
        
        ' Displays the current state of the SortedList.
        Console.WriteLine("After removing the element at index 5:")
        PrintKeysAndValues(mySL)
    End Sub
    
    
    Public Shared Sub PrintKeysAndValues(myList As SortedList)
        Console.WriteLine(ControlChars.Tab & "-KEY-" & ControlChars.Tab & _
           "-VALUE-")
        Dim i As Integer
        For i = 0 To myList.Count - 1
            Console.WriteLine(ControlChars.Tab & "{0}:" & ControlChars.Tab & _
               "{1}", myList.GetKey(i), myList.GetByIndex(i))
        Next i
        Console.WriteLine()
    End Sub
End Class

' This code produces the following output.
' 
' The SortedList initially contains the following:
'     -KEY-    -VALUE-
'     1a:    The
'     1b:    quick
'     1c:    brown
'     2a:    fox
'     2b:    jumps
'     2c:    over
'     3a:    the
'     3b:    lazy
'     3c:    dog
' 
' After removing "lazy":
'     -KEY-    -VALUE-
'     1a:    The
'     1b:    quick
'     1c:    brown
'     2a:    fox
'     2b:    jumps
'     2c:    over
'     3a:    the
'     3c:    dog
' 
' After removing the element at index 5:
'     -KEY-    -VALUE-
'     1a:    The
'     1b:    quick
'     1c:    brown
'     2a:    fox
'     2b:    jumps
'     3a:    the
'     3c:    dog

Remarks

The index sequence is based on the sort sequence. When an element is added, it is inserted into SortedList in the correct sort order, and the indexing adjusts accordingly. When an element is removed, the indexing also adjusts accordingly. Therefore, the index of a specific key/value pair might change as elements are added or removed from the SortedList object.

In collections of contiguous elements, such as lists, the elements that follow the removed element move up to occupy the vacated spot. If the collection is indexed, the indexes of the elements that are moved are also updated. This behavior does not apply to collections where elements are conceptually grouped into buckets, such as a hash table.

This method is an O(n) operation, where n is Count.

See also

• Remove(Object)