Remove all elements in a collection from a HashSet in C#

To remove all elements in a collection from a HashSet, the code is as follows −

Example

 Live Demo

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main(String[] args){
      HashSet<string> set1 = new HashSet<string>();
      set1.Add("Ryan");
      set1.Add("Tom");
      set1.Add("Andy");
      set1.Add("Tim");
      Console.WriteLine("Elements in HashSet1...");
      foreach (string res in set1){
         Console.WriteLine(res);
      }
      HashSet<string> set2 = new HashSet<string>();
      set2.Add("John");
      set2.Add("Jacob");
      set2.Add("Ryan");
      set2.Add("Tom");
      set2.Add("Andy");
      set2.Add("Tim");
      set2.Add("Steve");
      set2.Add("Mark");
      Console.WriteLine("Elements in HashSet2...");
      foreach (string res in set2){
         Console.WriteLine(res);
      }
      Console.WriteLine("Is HashSet1 equal to HashSet2? = "+set1.Equals(set2));
      set2.ExceptWith(set1);
      // displaying elements in set2, which are not on set1
      foreach(string i in set2){
         Console.WriteLine(i);
      }
   }
}

Output

This will produce the following output −

Elements in HashSet1...
Ryan
Tom
Andy
Tim
Elements in HashSet2...
John
Jacob
Ryan
Tom
Andy
Tim
Steve
Mark
Is HashSet1 equal to HashSet2? = False John
Jacob
Steve
Mark

Example

Let us see another example −

 Live Demo

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main(String[] args){
      HashSet<string> set1 = new HashSet<string>();
      set1.Add("Jacob");
      set1.Add("Ryan");
      set1.Add("Tom");
      set1.Add("Andy");
      set1.Add("Tim");
      set1.Add("Steve");
      set1.Add("Mark");
      Console.WriteLine("Elements in HashSet1...");
      foreach (string res in set1){
         Console.WriteLine(res);
      }
      HashSet<string> set2 = new HashSet<string>();
      set2.Add("Kevin");
      set2.Add("Jacob");
      set2.Add("Ryan");
      set2.Add("Tom");
      set2.Add("Andy");
      set2.Add("Tim");
      set2.Add("Steve");
      set2.Add("Mark");
      Console.WriteLine("Elements in HashSet2...");
      foreach (string res in set2){
         Console.WriteLine(res);
      }
      Console.WriteLine("Is HashSet1 equal to HashSet2? = "+set1.Equals(set2));
      set2.ExceptWith(set1);
      // displaying elements in set2, which are not on set1
      foreach(string i in set2){
         Console.WriteLine(i);
      }
   }
}

Output

This will produce the following output −

Elements in HashSet1...
Jacob
Ryan
Tom
Andy
Tim
Steve
Mark
Elements in HashSet2...
Kevin
Jacob
Ryan
Tom
Andy
Tim
Steve
Mark
Is HashSet1 equal to HashSet2? = False Kevin

AmitDiwan

Published on 05-Dec-2019 07:42:50

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