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List.Remove Method

.NET Framework 2.0

Other Versions

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

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

Syntax

C++

Copy

public bool Remove (
	T item
)

Copy

public final boolean Remove (
	T item
)

JScript

Copy

public final function Remove (
	item : T
) : boolean

XAML

Copy

Not applicable.

Parameters

item: The object to remove from the List. The value can be a null reference (Nothing in Visual Basic) for reference types.

Return Value

true if item is successfully removed; otherwise, false. This method also returns false if item was not found in the List.

Remarks

This method determines equality using the default equality comparer EqualityComparer.Default for T, the type of values in the list.

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

Example

The following code example demonstrates Remove method. Several properties and methods of the List generic class are used to add, insert, and search the list. After these operations, the list contains a duplicate. The Remove method is used to remove the first instance of the duplicate item, and the contents are displayed. The Remove method always removes the first instance it encounters.

C++

Copy

using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();

        Console.WriteLine("\nCapacity: {0}", dinosaurs.Capacity);

        dinosaurs.Add("Tyrannosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");
        dinosaurs.Add("Compsognathus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\nCapacity: {0}", dinosaurs.Capacity);
        Console.WriteLine("Count: {0}", dinosaurs.Count);

        Console.WriteLine("\nContains(\"Deinonychus\"): {0}",
            dinosaurs.Contains("Deinonychus"));

        Console.WriteLine("\nInsert(2, \"Compsognathus\")");
        dinosaurs.Insert(2, "Compsognathus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\ndinosaurs[3]: {0}", dinosaurs[3]);

        Console.WriteLine("\nRemove(\"Compsognathus\")");
        dinosaurs.Remove("Compsognathus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        dinosaurs.TrimExcess();
        Console.WriteLine("\nTrimExcess()");
        Console.WriteLine("Capacity: {0}", dinosaurs.Capacity);
        Console.WriteLine("Count: {0}", dinosaurs.Count);

        dinosaurs.Clear();
        Console.WriteLine("\nClear()");
        Console.WriteLine("Capacity: {0}", dinosaurs.Capacity);
        Console.WriteLine("Count: {0}", dinosaurs.Count);
    }
}

/* This code example produces the following output:

Capacity: 0

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus

Capacity: 8
Count: 5

Contains("Deinonychus"): True

Insert(2, "Compsognathus")

Tyrannosaurus
Amargasaurus
Compsognathus
Mamenchisaurus
Deinonychus
Compsognathus

dinosaurs[3]: Mamenchisaurus

Remove("Compsognathus")

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Deinonychus
Compsognathus

TrimExcess()
Capacity: 5
Count: 5

Clear()
Capacity: 5
Count: 0
 */

Platforms

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.

Version Information

.NET Framework

Supported in: 3.0, 2.0

.NET Compact Framework

Supported in: 2.0

XNA Framework

Supported in: 1.0

Reference

List Generic Class
List Members
System.Collections.Generic Namespace
RemoveAt
RemoveRange
List.Add Method
List.Insert Method

Other Resources

Performing Culture-Insensitive String Operations in Collections

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FAQ

You cannot remove an item while you're enumerating the list

If you try to remove an item while you are enumerating the list, this will result in an exception. Several ways to work around this are explained here: http://kristofverbiest.blogspot.com/2008/10/removing-items-from-collection.html

History

10/30/2008
Kristof Verbiest