C# | Removing the specified element from the List

List.Remove(T) Method is used to remove the first occurrence of a specific object from the List.

Properties of List:

• It is different from the arrays. A list can be resized dynamically but arrays cannot.
• List class can accept null as a valid value for reference types and it also allows duplicate elements.
• If the Count becomes equals to Capacity then the capacity of the List increases automatically by reallocating the internal array. The existing elements will be copied to the new array before the addition of the new element.

Syntax:

public bool Remove (T item);

Parameter:

item: Specified object which is to be remove from the List.

Return Type: This method returns True if item is successfully removed. Otherwise it returns False.

Note: This method returns False if item was not found in the List.

Below programs illustrate how to remove the specified element from the List:

Example 1:

// C# program to remove the specified
// element from the List<T>
using System;
using System.Collections.Generic;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {

        // Creating a List of integers
        List<int> firstlist = new List<int>();

        // adding elements in firstlist
        firstlist.Add(1);
        firstlist.Add(2);
        firstlist.Add(3);
        firstlist.Add(4);

        // Displaying elements of firstlist
        // by using foreach loop
        Console.WriteLine("Before Removing");
        foreach(int element in firstlist)
        {
            Console.WriteLine(element);
        }

        // Removing 2 from the firstlist & Displaying
        // the remaining firstlist elements
        Console.WriteLine("After Removing");
        firstlist.Remove(2);
        foreach(int element in firstlist)
        {
            Console.WriteLine(element);
        }
    }
}

Output:

Before Removing
1
2
3
4
After Removing
1
3
4

Example 2:

// C# program to remove the specified
// element from the List<T>
using System;
using System.Collections.Generic;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {

        // Creating a List of integers
        List<int> firstlist = new List<int>();

        // adding elements in firstlist
        firstlist.Add(1);
        firstlist.Add(2);
        firstlist.Add(3);
        firstlist.Add(4);

        // Adding some duplicate
        // elements in firstlist
        firstlist.Add(2);
        firstlist.Add(4);

        // Displaying elements of firstlist
        // by using foreach loop
        Console.WriteLine("Before Removing");
        foreach(int element in firstlist)
        {
            Console.WriteLine(element);
        }

        // Removing first occurrence of 2
        // from the firstlist & Displaying
        // the remaining firstlist elements
        Console.WriteLine("After Removing");
        firstlist.Remove(2);
        foreach(int element in firstlist)
        {
            Console.WriteLine(element);
        }
    }
}

Output:

Before Removing
1
2
3
4
2
4
After Removing
1
3
4
2
4

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1.remove?view=netframework-4.7.2