HashSet C# (How It Works For Developers)

Programming in C# is flexible and provides a large array of data structures to effectively manage various jobs. The HashSet is one such potent data structure that offers distinct components and constant-time average complexity for fundamental operations. This post will examine the use of HashSet in C# and how it may be used with IronPDF, a powerful library for working with PDF documents.

How to use HashSet in C\

1. Create a new Console App project.
2. Create an object for the HashSet in C#. Add the default value to the HashSet.
3. While adding, HashSet will automatically remove duplicate elements by checking if the element exists.
4. Process the HashSet only unique elements one by one.
5. Display the result and dispose of the object.

Understanding HashSet in C\

HashSet in C# is designed to provide high-performance set operations. A HashSet is the perfect collection to use in situations when you need to keep a distinct set of data since it prevents duplicate elements. It's included in the System.Collections.Generic namespace and provides quick insertion, deletion, faster retrieval, and lookup operations. In C#, use HashSet set operations methods that let you easily carry out standard set operations. The HashSet class provides set operations methods.

The following are a few C# uses for a HashSet:

Initialization and Basic Operations

Establishing a HashSet and carrying out fundamental actions such as appending, deleting, and verifying the existence of entries.

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // Initializes a HashSet of integers
        HashSet<int> numbers = new HashSet<int>();

        // Adds elements to the HashSet
        numbers.Add(1);
        numbers.Add(2);
        numbers.Add(3);

        // Removes an element from the HashSet
        numbers.Remove(2);

        // Checks for membership of an element
        bool containsThree = numbers.Contains(3);

        Console.WriteLine($"Contains 3: {containsThree}");
    }
}

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // Initializes a HashSet of integers
        HashSet<int> numbers = new HashSet<int>();

        // Adds elements to the HashSet
        numbers.Add(1);
        numbers.Add(2);
        numbers.Add(3);

        // Removes an element from the HashSet
        numbers.Remove(2);

        // Checks for membership of an element
        bool containsThree = numbers.Contains(3);

        Console.WriteLine($"Contains 3: {containsThree}");
    }
}

Imports System
Imports System.Collections.Generic

Friend Class Program
	Shared Sub Main()
		' Initializes a HashSet of integers
		Dim numbers As New HashSet(Of Integer)()

		' Adds elements to the HashSet
		numbers.Add(1)
		numbers.Add(2)
		numbers.Add(3)

		' Removes an element from the HashSet
		numbers.Remove(2)

		' Checks for membership of an element
		Dim containsThree As Boolean = numbers.Contains(3)

		Console.WriteLine($"Contains 3: {containsThree}")
	End Sub
End Class

Initialization with Collection

Using an existing collection as the starting point for a HashSet, duplicates are immediately eliminated.

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // Creates a list with duplicate elements
        List<int> duplicateNumbers = new List<int> { 1, 2, 2, 3, 3, 4 };

        // Initializes a HashSet with the list, automatically removes duplicates
        HashSet<int> uniqueNumbers = new HashSet<int>(duplicateNumbers);

        Console.WriteLine("Unique numbers:");
        foreach (var number in uniqueNumbers)
        {
            Console.WriteLine(number);
        }
    }
}

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // Creates a list with duplicate elements
        List<int> duplicateNumbers = new List<int> { 1, 2, 2, 3, 3, 4 };

        // Initializes a HashSet with the list, automatically removes duplicates
        HashSet<int> uniqueNumbers = new HashSet<int>(duplicateNumbers);

        Console.WriteLine("Unique numbers:");
        foreach (var number in uniqueNumbers)
        {
            Console.WriteLine(number);
        }
    }
}

Imports System
Imports System.Collections.Generic

Friend Class Program
	Shared Sub Main()
		' Creates a list with duplicate elements
		Dim duplicateNumbers As New List(Of Integer) From {1, 2, 2, 3, 3, 4}

		' Initializes a HashSet with the list, automatically removes duplicates
		Dim uniqueNumbers As New HashSet(Of Integer)(duplicateNumbers)

		Console.WriteLine("Unique numbers:")
		For Each number In uniqueNumbers
			Console.WriteLine(number)
		Next number
	End Sub
End Class

Union with Another HashSet

Combining two HashSet instances to produce a new set that combines distinct items from both sets using the UnionWith function.

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 3, 4, 5 };

        // Merges set2 into set1
        set1.UnionWith(set2);

        Console.WriteLine("Union of set1 and set2:");
        foreach (var item in set1)
        {
            Console.WriteLine(item);
        }
    }
}

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 3, 4, 5 };

        // Merges set2 into set1
        set1.UnionWith(set2);

        Console.WriteLine("Union of set1 and set2:");
        foreach (var item in set1)
        {
            Console.WriteLine(item);
        }
    }
}

Imports System
Imports System.Collections.Generic

Friend Class Program
	Shared Sub Main()
		Dim set1 As New HashSet(Of Integer) From {1, 2, 3}
		Dim set2 As New HashSet(Of Integer) From {3, 4, 5}

		' Merges set2 into set1
		set1.UnionWith(set2)

		Console.WriteLine("Union of set1 and set2:")
		For Each item In set1
			Console.WriteLine(item)
		Next item
	End Sub
End Class

Intersection with Another HashSet

Using the IntersectWith function, determine the shared components between two HashSet instances.

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 3, 4, 5 };

        // Keeps only elements that are present in both sets
        set1.IntersectWith(set2);

        Console.WriteLine("Intersection of set1 and set2:");
        foreach (var item in set1)
        {
            Console.WriteLine(item);
        }
    }
}

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 3, 4, 5 };

        // Keeps only elements that are present in both sets
        set1.IntersectWith(set2);

        Console.WriteLine("Intersection of set1 and set2:");
        foreach (var item in set1)
        {
            Console.WriteLine(item);
        }
    }
}

Imports System
Imports System.Collections.Generic

Friend Class Program
	Shared Sub Main()
		Dim set1 As New HashSet(Of Integer) From {1, 2, 3}
		Dim set2 As New HashSet(Of Integer) From {3, 4, 5}

		' Keeps only elements that are present in both sets
		set1.IntersectWith(set2)

		Console.WriteLine("Intersection of set1 and set2:")
		For Each item In set1
			Console.WriteLine(item)
		Next item
	End Sub
End Class

Difference with Another HashSet

Using the ExceptWith function, find the elements that are in one HashSet but not in another.

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 3, 4, 5 };

        // Removes elements from set1 that are also in set2
        set1.ExceptWith(set2);

        Console.WriteLine("Difference of set1 and set2:");
        foreach (var item in set1)
        {
            Console.WriteLine(item);
        }
    }
}

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 3, 4, 5 };

        // Removes elements from set1 that are also in set2
        set1.ExceptWith(set2);

        Console.WriteLine("Difference of set1 and set2:");
        foreach (var item in set1)
        {
            Console.WriteLine(item);
        }
    }
}

Imports System
Imports System.Collections.Generic

Friend Class Program
	Shared Sub Main()
		Dim set1 As New HashSet(Of Integer) From {1, 2, 3}
		Dim set2 As New HashSet(Of Integer) From {3, 4, 5}

		' Removes elements from set1 that are also in set2
		set1.ExceptWith(set2)

		Console.WriteLine("Difference of set1 and set2:")
		For Each item In set1
			Console.WriteLine(item)
		Next item
	End Sub
End Class

Checking for Subset or Superset:

Using the IsSubsetOf and IsSupersetOf methods, one may ascertain whether a given HashSet instance is a subset or superset of another.

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 2, 3 };

        // Checks if set2 is a subset of set1
        bool isSubset = set2.IsSubsetOf(set1);

        // Checks if set1 is a superset of set2
        bool isSuperset = set1.IsSupersetOf(set2);

        Console.WriteLine($"Is set2 a subset of set1: {isSubset}");
        Console.WriteLine($"Is set1 a superset of set2: {isSuperset}");
    }
}

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 2, 3 };

        // Checks if set2 is a subset of set1
        bool isSubset = set2.IsSubsetOf(set1);

        // Checks if set1 is a superset of set2
        bool isSuperset = set1.IsSupersetOf(set2);

        Console.WriteLine($"Is set2 a subset of set1: {isSubset}");
        Console.WriteLine($"Is set1 a superset of set2: {isSuperset}");
    }
}

Imports System
Imports System.Collections.Generic

Friend Class Program
	Shared Sub Main()
		Dim set1 As New HashSet(Of Integer) From {1, 2, 3}
		Dim set2 As New HashSet(Of Integer) From {2, 3}

		' Checks if set2 is a subset of set1
		Dim isSubset As Boolean = set2.IsSubsetOf(set1)

		' Checks if set1 is a superset of set2
		Dim isSuperset As Boolean = set1.IsSupersetOf(set2)

		Console.WriteLine($"Is set2 a subset of set1: {isSubset}")
		Console.WriteLine($"Is set1 a superset of set2: {isSuperset}")
	End Sub
End Class

Symmetric Difference

Using the SymmetricExceptWith technique, determine the symmetric difference (elements present in one set, but not in both).

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 3, 4, 5 };

        // Keeps elements that are in set1 or set2 but not in both
        set1.SymmetricExceptWith(set2);

        Console.WriteLine("Symmetric difference of set1 and set2:");
        foreach (var item in set1)
        {
            Console.WriteLine(item);
        }
    }
}

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> set1 = new HashSet<int> { 1, 2, 3 };
        HashSet<int> set2 = new HashSet<int> { 3, 4, 5 };

        // Keeps elements that are in set1 or set2 but not in both
        set1.SymmetricExceptWith(set2);

        Console.WriteLine("Symmetric difference of set1 and set2:");
        foreach (var item in set1)
        {
            Console.WriteLine(item);
        }
    }
}

Imports System
Imports System.Collections.Generic

Friend Class Program
	Shared Sub Main()
		Dim set1 As New HashSet(Of Integer) From {1, 2, 3}
		Dim set2 As New HashSet(Of Integer) From {3, 4, 5}

		' Keeps elements that are in set1 or set2 but not in both
		set1.SymmetricExceptWith(set2)

		Console.WriteLine("Symmetric difference of set1 and set2:")
		For Each item In set1
			Console.WriteLine(item)
		Next item
	End Sub
End Class

IronPDF

Programmers may use the C# language to produce, edit, and modify PDF documents by utilizing the IronPDF .NET library. The application offers a wide range of tools and features to enable different operations with PDF files, including creating new PDFs from HTML, converting HTML to PDF, combining or dividing PDF documents, and annotating existing PDFs with text, photos, and other data. To know more about the IronPDF, refer to the official documentation.

IronPDF excels in HTML to PDF conversion, ensuring precise preservation of original layouts and styles. It's perfect for creating PDFs from web-based content such as reports, invoices, and documentation. With support for HTML files, URLs, and raw HTML strings, IronPDF easily produces high-quality PDF documents.

using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();

        // 1. Convert HTML String to PDF
        var htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>";
        var pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent);
        pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf");

        // 2. Convert HTML File to PDF
        var htmlFilePath = "path_to_your_html_file.html"; // Specify the path to your HTML file
        var pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath);
        pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf");

        // 3. Convert URL to PDF
        var url = "http://ironpdf.com"; // Specify the URL
        var pdfFromUrl = renderer.RenderUrlAsPdf(url);
        pdfFromUrl.SaveAs("URLToPDF.pdf");
    }
}

using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();

        // 1. Convert HTML String to PDF
        var htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>";
        var pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent);
        pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf");

        // 2. Convert HTML File to PDF
        var htmlFilePath = "path_to_your_html_file.html"; // Specify the path to your HTML file
        var pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath);
        pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf");

        // 3. Convert URL to PDF
        var url = "http://ironpdf.com"; // Specify the URL
        var pdfFromUrl = renderer.RenderUrlAsPdf(url);
        pdfFromUrl.SaveAs("URLToPDF.pdf");
    }
}

Imports IronPdf

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		Dim renderer = New ChromePdfRenderer()

		' 1. Convert HTML String to PDF
		Dim htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>"
		Dim pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent)
		pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf")

		' 2. Convert HTML File to PDF
		Dim htmlFilePath = "path_to_your_html_file.html" ' Specify the path to your HTML file
		Dim pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath)
		pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf")

		' 3. Convert URL to PDF
		Dim url = "http://ironpdf.com" ' Specify the URL
		Dim pdfFromUrl = renderer.RenderUrlAsPdf(url)
		pdfFromUrl.SaveAs("URLToPDF.pdf")
	End Sub
End Class

Features of IronPDF

• HTML to PDF conversion: Any kind of HTML data, including files, URLs, and HTML code strings, may be converted into PDF documents with IronPDF.
• PDF Generation: Text, images, and other objects may be programmatically added to PDF documents using the C# programming language.
• PDF Manipulation: IronPDF can divide a PDF file into numerous files and edit pre-existing PDF files. It can merge several PDF files into a single file.
• PDF Forms: Because the library enables users to build and complete PDF forms, it is useful in scenarios where form data needs to be gathered and processed.
• Security Features: IronPDF allows for PDF document encryption as well as password and permission security.

Install IronPDF

Acquire the IronPDF library; the upcoming patch requires it. To do this, enter the following code into the Package Manager:

Install-Package IronPdf

or

dotnet add package IronPdf

Another option is to look for the package "IronPDF" using the NuGet Package Manager. From all the NuGet packages related to IronPDF, we may select and download the required package from this list.

HashSet with IronPDF

Within the C# environment, IronPDF is a powerful library that makes working with PDF documents easier. In situations where distinct data representation and effective document creation are crucial, combining the efficiency of HashSet with the document manipulation powers of IronPDF might result in creative solutions.

Benefits of Using HashSet with IronPDF

• Data Redundancy Reduction: By ensuring that only distinct elements are kept, HashSets help to avoid data duplication. When dealing with huge datasets to remove duplicate information, this is quite helpful.
• Effective Lookup: Basic operations such as insertion, deletion, and lookup may be performed with constant-time average complexity using HashSet. This kind of performance is very important when working with different-sized datasets.
• Simplified Production of Documents: IronPDF streamlines the C# PDF document creation process. You may establish fast and effective processes for producing original and dynamic content for your PDFs by integrating HashSet with IronPDF.

Now let's look at a real-world scenario where using HashSet with IronPDF might be useful.

Generating PDF with Unique Data

using IronPdf;
using System;
using System.Collections.Generic;

class PdfGenerator
{
    static void Main()
    {
        // Sample user names with duplicates
        string[] userNames = { "Alice", "Bob", "Charlie", "Bob", "David", "Alice" };

        // Using HashSet to ensure unique user names
        HashSet<string> uniqueUserNames = new HashSet<string>(userNames);

        // Generating PDF with unique user names
        GeneratePdf(uniqueUserNames);
    }

    static void GeneratePdf(HashSet<string> uniqueUserNames)
    {
        // Create a new PDF document using IronPDF
        HtmlToPdf renderer = new HtmlToPdf();

        // Render a PDF from an HTML document consisting of unique user names
        var pdf = renderer.RenderHtmlAsPdf(BuildHtmlDocument(uniqueUserNames));

        // Save the PDF to a file
        string pdfFilePath = "UniqueUserNames.pdf";
        pdf.SaveAs(pdfFilePath);

        // Display a message with the file path
        Console.WriteLine($"PDF generated successfully. File saved at: {pdfFilePath}");
    }

    static string BuildHtmlDocument(HashSet<string> uniqueUserNames)
    {
        // Build an HTML document with unique user names
        string htmlDocument = "<html><body><ul>";
        foreach (var userName in uniqueUserNames)
        {
            htmlDocument += $"<li>{userName}</li>";
        }
        htmlDocument += "</ul></body></html>";
        return htmlDocument;
    }
}

using IronPdf;
using System;
using System.Collections.Generic;

class PdfGenerator
{
    static void Main()
    {
        // Sample user names with duplicates
        string[] userNames = { "Alice", "Bob", "Charlie", "Bob", "David", "Alice" };

        // Using HashSet to ensure unique user names
        HashSet<string> uniqueUserNames = new HashSet<string>(userNames);

        // Generating PDF with unique user names
        GeneratePdf(uniqueUserNames);
    }

    static void GeneratePdf(HashSet<string> uniqueUserNames)
    {
        // Create a new PDF document using IronPDF
        HtmlToPdf renderer = new HtmlToPdf();

        // Render a PDF from an HTML document consisting of unique user names
        var pdf = renderer.RenderHtmlAsPdf(BuildHtmlDocument(uniqueUserNames));

        // Save the PDF to a file
        string pdfFilePath = "UniqueUserNames.pdf";
        pdf.SaveAs(pdfFilePath);

        // Display a message with the file path
        Console.WriteLine($"PDF generated successfully. File saved at: {pdfFilePath}");
    }

    static string BuildHtmlDocument(HashSet<string> uniqueUserNames)
    {
        // Build an HTML document with unique user names
        string htmlDocument = "<html><body><ul>";
        foreach (var userName in uniqueUserNames)
        {
            htmlDocument += $"<li>{userName}</li>";
        }
        htmlDocument += "</ul></body></html>";
        return htmlDocument;
    }
}

Imports IronPdf
Imports System
Imports System.Collections.Generic

Friend Class PdfGenerator
	Shared Sub Main()
		' Sample user names with duplicates
		Dim userNames() As String = { "Alice", "Bob", "Charlie", "Bob", "David", "Alice" }

		' Using HashSet to ensure unique user names
		Dim uniqueUserNames As New HashSet(Of String)(userNames)

		' Generating PDF with unique user names
		GeneratePdf(uniqueUserNames)
	End Sub

	Private Shared Sub GeneratePdf(ByVal uniqueUserNames As HashSet(Of String))
		' Create a new PDF document using IronPDF
		Dim renderer As New HtmlToPdf()

		' Render a PDF from an HTML document consisting of unique user names
		Dim pdf = renderer.RenderHtmlAsPdf(BuildHtmlDocument(uniqueUserNames))

		' Save the PDF to a file
		Dim pdfFilePath As String = "UniqueUserNames.pdf"
		pdf.SaveAs(pdfFilePath)

		' Display a message with the file path
		Console.WriteLine($"PDF generated successfully. File saved at: {pdfFilePath}")
	End Sub

	Private Shared Function BuildHtmlDocument(ByVal uniqueUserNames As HashSet(Of String)) As String
		' Build an HTML document with unique user names
		Dim htmlDocument As String = "<html><body><ul>"
		For Each userName In uniqueUserNames
			htmlDocument &= $"<li>{userName}</li>"
		Next userName
		htmlDocument &= "</ul></body></html>"
		Return htmlDocument
	End Function
End Class

In the above code example, we save unique user names retrieved from an array using a HashSet uniqueUserNames. The HashSet automatically eliminates duplicates. Next, we create an unordered list of these distinct user names in a PDF document using IronPDF. To know more about the code, check using HTML to create a PDF.

OUTPUT

Conclusion

To sum up, the C# HashSet data structure is an effective tool for organizing sets of distinct items. It creates new opportunities for dynamic, one-of-a-kind, and performance-optimized PDF document creation when paired with IronPDF.

We illustrated how to use HashSet to guarantee data uniqueness while using IronPDF to create PDF documents in the example that was given. Building strong and effective C# applications may benefit from the combination of HashSet and IronPDF, whether you're working on data deduplication, reporting, or managing dynamic content. As you investigate more, take into account the many contexts in which you might utilize this combination to improve the usability and functionality of your apps.

The $749 Lite version of IronPDF comes with a permanent license, upgrade options, and a year of software support. Throughout the watermarked trial period on licensing to find out more about IronPDF's price, licensing, and free trial. Visit the Iron Software website for further information on Iron Software.