C# | Adding the elements of the specified collection to the end of the List

List<T>.AddRange(IEnumerable<T>) Method is used to add the elements of the specified collection to the end of the List<T>.

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 void AddRange (System.Collections.Generic.IEnumerable<T> collection);

Parameter:

collection: It is the specified collection whose elements will be added to the end of the List<T>.

Exception: This method will give ArgumentNullException if the collection is null.

Note: The collection itself cannot be null, but it can contain elements that are null if type T is a reference type. The order of the elements in the collection is always preserved in the List<T>.

Below programs illustrate the use of above discussed method:

Example 1:

filter_none

edit
close

play_arrow

link
brightness_4
code

// C# program to illustrate the
// List.AddRange Method
using System;
using System.Collections.Generic;
  
class Geeks {
  
    // Main Method
    public static void Main(String[] args)
    {
  
        // Creating a List of Strings
        List<String> firstlist = new List<String>();
  
        // adding elements in firstlist
        firstlist.Add("Geeks");
        firstlist.Add("GFG");
        firstlist.Add("C#");
        firstlist.Add("Tutorials");
  
        Console.WriteLine("Before AddRange Method");
        Console.WriteLine();
  
        // displaying the item of List
        foreach(String str in firstlist)
        {
            Console.WriteLine(str);
        }
  
        Console.WriteLine("\nAfter AddRange Method\n");
  
        // Here we are using AddRange method
        // Which adds the elements of firstlist
        // Collection in firstlist again i.e.
        // we have copied the whole firstlist
        // in it
        firstlist.AddRange(firstlist);
  
        // displaying the item of List
        foreach(String str in firstlist)
        {
            Console.WriteLine(str);
        }
    }
}

chevron_right


Output:

Before AddRange Method

Geeks
GFG
C#
Tutorials

After AddRange Method

Geeks
GFG
C#
Tutorials
Geeks
GFG
C#
Tutorials

Example 2:

filter_none

edit
close

play_arrow

link
brightness_4
code

// C# program to illustrate the
// List.AddRange Method
using System;
using System.Collections.Generic;
  
class Geeks {
  
    // Main Method
    public static void Main(String[] args)
    {
  
        // Creating a List of Strings
        List<String> firstlist = new List<String>();
  
        // adding elements in firstlist
        firstlist.Add("Geeks");
        firstlist.Add("GFG");
        firstlist.Add("C#");
        firstlist.Add("Tutorials");
  
        Console.WriteLine("Before AddRange Method");
        Console.WriteLine();
  
        // displaying the item of List
        foreach(String str in firstlist)
        {
            Console.WriteLine(str);
        }
  
        Console.WriteLine("\nAfter AddRange Method\n");
  
        // taking array of String
        string[] str_add = { "Collections",
                             "Generic",
                             "List" };
  
        // here we are adding the elements
        // of the str_add to the end of
        // the List<T>.
        firstlist.AddRange(str_add);
  
        // displaying the item of List
        foreach(String str in firstlist)
        {
            Console.WriteLine(str);
        }
    }
}

chevron_right


Output:

Before AddRange Method

Geeks
GFG
C#
Tutorials

After AddRange Method

Geeks
GFG
C#
Tutorials
Collections
Generic
List

Reference:



My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.