What is the HashSet, C# Set collection in C#?

HashSet in C# eliminates duplicate strings or elements in an array.In C#, it is an optimized set collection.

Let us see an example to remove duplicate strings using C# HashSet −

Example

using System;
using System.Collections.Generic;
using System.Linq;

class Program {
   static void Main() {
      string[] arr1 = {
         "one",
         "two",
         "two",
         "one",
         "three"
      };

      Console.WriteLine(string.Join(",", arr1));

      // HashSet
      var h = new HashSet(arr1);

      // eliminates duplicate words
      string[] arr2 = h.ToArray();

      Console.WriteLine(string.Join(",", arr2));
   }
}

To declare HashSet.

var h = new HashSet<string7gt;(arr1);

Now set it on the array to remove the duplicate words −

string[] arr2 = h.ToArray();