C# | Removing a range of elements from the List
List<T>.RemoveRange(Int32, Int32) Method is used to remove a range of elements from 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 RemoveRange (int index, int count);
Parameters:
index: It is the zero-based starting index of the range of elements which is to be removed. count: It is the number of the elements which is to be removed.
Exceptions:
Below programs illustrate the use of List<T>.RemoveRange(Int32, Int32) Method: Example 1:
CSharp
// C# Program to remove a range of // elements from the List using System; using System.Collections; using System.Collections.Generic; class Beginner { // Main Method public static void Main(String[] args) { // Creating an List<T> of strings List<String> firstlist = new List<String>(); // Adding elements to List firstlist.Add( "Beginner" ); firstlist.Add( "For" ); firstlist.Add( "Beginner" ); firstlist.Add( "GFG" ); firstlist.Add( "C#" ); firstlist.Add( "Tutorials" ); firstlist.Add( "w3wiki" ); // Displaying the elements of firstlist Console.WriteLine( "Elements in List:\n" ); foreach ( string ele in firstlist) { Console.WriteLine(ele); } // removing 1 elements starting // from index 3 firstlist.RemoveRange(3, 1); Console.WriteLine( "" ); // Displaying the updated List Console.WriteLine( "After Removing of elements:\n" ); // Displaying the elements in List foreach ( string ele in firstlist) { Console.WriteLine(ele); } } } |
Output:
Elements in List: Beginner For Beginner GFG C# Tutorials w3wiki After Removing of elements: Beginner For Beginner C# Tutorials w3wiki
Time Complexity: O(n)
Auxiliary Space: O(n)
Example 2:
CSharp
// C# Program to remove a range of // elements from the List using System; using System.Collections; using System.Collections.Generic; class Beginner { // Main Method public static void Main(String[] args) { // Creating an List<T> of Integers List< int > firstlist = new List< int >(); // Adding elements to List firstlist.Add(1); firstlist.Add(2); firstlist.Add(3); firstlist.Add(4); firstlist.Add(5); firstlist.Add(6); firstlist.Add(7); // Displaying the elements of firstlist Console.WriteLine( "Elements in List:\n" ); foreach ( int ele in firstlist) { Console.WriteLine(ele); } // removing 2 elements starting // from index 3 i.e 3rd and 4th firstlist.RemoveRange(3, 2); Console.WriteLine( "" ); // Displaying the updated List Console.WriteLine( "After Removing of elements:\n" ); // Displaying the elements in List foreach ( int ele in firstlist) { Console.WriteLine(ele); } } } |
Output:
Elements in List: 1 2 3 4 5 6 7 After Removing of elements: 1 2 3 6 7
Time complexity: O(n) since using a loop
Auxiliary Space: O(n) where n is size of the list
Reference:
- https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1.removerange?view=netframework-4.7.2
Contact Us