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List<T>.InsertRange() method with example in C#

C# List<T>.InsertRange() method: Here, we are going to learn about the InsertRange() method of List with example.
Submitted by IncludeHelp, on March 16, 2019

C# List<T>.InsertRange() Method

List<T>.InsertRange() method is used to insert a collection of elements of same type at specified index in the list.

Syntax:

    void List<T>.InsertRange(int index, IEnumerable<T> collection);

Parameter: It accepts two parameters 1) index – where you want to insert the elements and 2) collection – a collection of the elements of type T.

Return value: It returns nothing – it's return type is void.

Example:

    int list declaration:
    List<int> a = new List<int>();

    adding elements:
    a.Add(10);
    a.Add(20);
    a.Add(30);
    a.Add(40);
    a.Add(50);
    
    //inserting elements (array) at specified indexes
    int[] arr = { 100, 200, 300 };
    a.InsertRange(3, arr);
    
    Output:
    10 20 30 100 200 300 40 50

C# Example to insert collection of elements at specified index in the list using List<T>.InsertRange() Method

using System;
using System.Text;
using System.Collections.Generic;

namespace Test
{
    class Program
    {
        static void printList(List<int> lst)
        {
            //printing elements
            foreach (int item in lst)
            {
                Console.Write(item + " ");
            }
            Console.WriteLine();
        }

        static void Main(string[] args)
        {
            //integer list
            List<int> a = new List<int>();

            //adding elements
            a.Add(10);
            a.Add(20);
            a.Add(30);
            a.Add(40);
            a.Add(50);

            //print the list
            Console.WriteLine("list elements...");
            printList(a);

            //inserting elements (array) at specified indexes
            int[] arr = { 100, 200, 300 };
            a.InsertRange(3, arr);

            //list after inserting elements
            Console.WriteLine("list elements after inserting elements...");
            printList(a);

            //hit ENTER to exit
            Console.ReadLine();
        }
    }
}

Output

list elements...
10 20 30 40 50
list elements after inserting elements...
10 20 30 100 200 300 40 50

Reference: List<T>.InsertRange(Int32, IEnumerable<T>) Method