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ArrayList.Remove Method

Removes the first occurrence of a specific object from the ArrayList.

Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)

public virtual void Remove (
	Object obj
)
public void Remove (
	Object obj
)
public function Remove (
	obj : Object
)
Not applicable.

Parameters

obj

The Object to remove from the ArrayList. The value can be a null reference (Nothing in Visual Basic).

Exception typeCondition

NotSupportedException

The ArrayList is read-only.

-or-

The ArrayList has a fixed size.

If the ArrayList does not contain the specified object, the ArrayList remains unchanged. No exception is thrown.

This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

This method determines equality by calling Object.Equals.

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.

The following code example shows how to remove elements from the 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( "jumped" );
      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   jumped   over   the   lazy   dog
After removing "lazy":
   The   quick   brown   fox   jumped   over   the   dog
After removing the element at index 5:
   The   quick   brown   fox   jumped   the   dog
After removing three elements starting at index 4:
   The   quick   brown   fox
*/ 

import System.*;
import System.Collections.*;

public class SamplesArrayList
{
    public static void main(String[] args)
    {
        // Creates and initializes a new ArrayList.
        ArrayList myAL = new ArrayList();

        myAL.Add("The");
        myAL.Add("quick");
        myAL.Add("brown");
        myAL.Add("fox");
        myAL.Add("jumped");
        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);
    } //main

    public static void PrintValues(IEnumerable myList)
    {
        IEnumerator objMyEnum = myList.GetEnumerator();
        while (objMyEnum.MoveNext()) {
            Object obj = objMyEnum.get_Current();
            Console.Write("   {0}", obj);
        }
        Console.WriteLine();
    } //PrintValues
} //SamplesArrayList 
/* 
 This code produces the following output.
 
 The ArrayList initially contains the following:
    The   quick   brown   fox   jumped   over   the   lazy   dog
 After removing "lazy":
    The   quick   brown   fox   jumped   over   the   dog
 After removing the element at index 5:
    The   quick   brown   fox   jumped   the   dog
 After removing three elements starting at index 4:
    The   quick   brown   fox
 */

import System;
import System.Collections;

// Creates and initializes a new ArrayList.
var myAL : ArrayList = new ArrayList();
myAL.Add( "The" );
myAL.Add( "quick" );
myAL.Add( "brown" );
myAL.Add( "fox" );
myAL.Add( "jumped" );
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 );

function PrintValues( myList : IEnumerable )  {
   var myEnumerator : System.Collections.IEnumerator  = myList.GetEnumerator();
   while ( myEnumerator.MoveNext() )
      Console.Write( "\t{0}", myEnumerator.Current );
   Console.WriteLine();
}
 /* 
 This code produces the following output.
 
 The ArrayList initially contains the following:
     The    quick    brown    fox    jumped    over    the    lazy    dog
 After removing "lazy":
     The    quick    brown    fox    jumped    over    the    dog
 After removing the element at index 5:
     The    quick    brown    fox    jumped    the    dog
 After removing three elements starting at index 4:
     The    quick    brown    fox
 */ 

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0

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