C# LINQ Distinct (How It Works For Developers)

Language-integrated query (LINQ), a potent language feature in C#, enables programmers to create clear, expressive queries for a variety of data sources. This post will discuss the use of IronPDF, a versatile C# library for working with PDF documents, using LINQ's Distinct function. We will show how this combination may make the process of creating unique documents from a collection easier. In this article, we are going to learn about the C# LINQ distinct function with IronPDF.

How to Use C# LINQ Distinct Method

1. Create a new console project.
2. Import System.Linq namespace.
3. Create a list with multiple items.
4. Call the method Distinct() from the List.
5. Get the unique values and display the result on the console.
6. Dispose of all the created objects.

What is LINQ

Developers may build clear and expressive queries for data manipulation directly in their code with C#'s LINQ (Language Integrated Query) feature. First included in the .NET Framework 3.5, LINQ offers a standard syntax for querying a range of data sources, including databases and collections. LINQ makes simple tasks like filtering and projection easier using operators like Where and Select, which improves code readability. Because it allows for delayed execution for optimal speed, this feature is crucial for C# developers to ensure that data manipulation operations are completed quickly and naturally in a manner analogous to SQL.

Understanding LINQ Distinct

Duplicate elements may be removed from a collection or sequence using LINQ's Distinct function. In the absence of a custom equality comparer, it compares items using their default comparer. This makes it a great option in situations when you need to work with a unique collection and remove duplicate components. The Distinct technique uses the default equality comparers to evaluate values. It will exclude duplicates to return only unique elements.

Basic Usage

To obtain distinct items, the simplest way to use it is to use the Distinct method directly on a collection.

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

public class DistinctExample
{
    public static void Example()
    {
        // Example list with duplicate integers
        List<int> numbers = new List<int> { 1, 2, 2, 3, 4, 4, 5 };

        // Using Distinct to remove duplicates
        var distinctNumbers = numbers.Distinct();

        // Display the distinct numbers
        foreach (var number in distinctNumbers)
        {
            Console.WriteLine(number);
        }
    }
}

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

public class DistinctExample
{
    public static void Example()
    {
        // Example list with duplicate integers
        List<int> numbers = new List<int> { 1, 2, 2, 3, 4, 4, 5 };

        // Using Distinct to remove duplicates
        var distinctNumbers = numbers.Distinct();

        // Display the distinct numbers
        foreach (var number in distinctNumbers)
        {
            Console.WriteLine(number);
        }
    }
}

Imports System.Linq
Imports System.Collections.Generic

Public Class DistinctExample
	Public Shared Sub Example()
		' Example list with duplicate integers
		Dim numbers As New List(Of Integer) From {1, 2, 2, 3, 4, 4, 5}

		' Using Distinct to remove duplicates
		Dim distinctNumbers = numbers.Distinct()

		' Display the distinct numbers
		For Each number In distinctNumbers
			Console.WriteLine(number)
		Next number
	End Sub
End Class

Custom Equality Comparer

You can define a custom equality comparison by using an overload of the Distinct function. This is helpful if you wish to compare items according to particular standards. Please refer to the following example:

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

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

public class PersonEqualityComparer : IEqualityComparer<Person>
{
    public bool Equals(Person x, Person y)
    {
        return x.FirstName == y.FirstName && x.LastName == y.LastName;
    }

    public int GetHashCode(Person obj)
    {
        return obj.FirstName.GetHashCode() ^ obj.LastName.GetHashCode();
    }
}

public class DistinctCustomComparerExample
{
    public static void Example()
    {
        // Example list of people
        List<Person> people = new List<Person>
        {
            new Person { FirstName = "John", LastName = "Doe" },
            new Person { FirstName = "Jane", LastName = "Doe" },
            new Person { FirstName = "John", LastName = "Doe" }
        };

        // Using Distinct with a custom equality comparer
        var distinctPeople = people.Distinct(new PersonEqualityComparer());

        // Display distinct people
        foreach (var person in distinctPeople)
        {
            Console.WriteLine($"{person.FirstName} {person.LastName}");
        }
    }
}

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

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

public class PersonEqualityComparer : IEqualityComparer<Person>
{
    public bool Equals(Person x, Person y)
    {
        return x.FirstName == y.FirstName && x.LastName == y.LastName;
    }

    public int GetHashCode(Person obj)
    {
        return obj.FirstName.GetHashCode() ^ obj.LastName.GetHashCode();
    }
}

public class DistinctCustomComparerExample
{
    public static void Example()
    {
        // Example list of people
        List<Person> people = new List<Person>
        {
            new Person { FirstName = "John", LastName = "Doe" },
            new Person { FirstName = "Jane", LastName = "Doe" },
            new Person { FirstName = "John", LastName = "Doe" }
        };

        // Using Distinct with a custom equality comparer
        var distinctPeople = people.Distinct(new PersonEqualityComparer());

        // Display distinct people
        foreach (var person in distinctPeople)
        {
            Console.WriteLine($"{person.FirstName} {person.LastName}");
        }
    }
}

Imports System
Imports System.Collections.Generic
Imports System.Linq

Public Class Person
	Public Property FirstName() As String
	Public Property LastName() As String
End Class

Public Class PersonEqualityComparer
	Implements IEqualityComparer(Of Person)

	Public Function Equals(ByVal x As Person, ByVal y As Person) As Boolean Implements IEqualityComparer(Of Person).Equals
		Return x.FirstName = y.FirstName AndAlso x.LastName = y.LastName
	End Function

	Public Function GetHashCode(ByVal obj As Person) As Integer Implements IEqualityComparer(Of Person).GetHashCode
		Return obj.FirstName.GetHashCode() Xor obj.LastName.GetHashCode()
	End Function
End Class

Public Class DistinctCustomComparerExample
	Public Shared Sub Example()
		' Example list of people
		Dim people As New List(Of Person) From {
			New Person With {
				.FirstName = "John",
				.LastName = "Doe"
			},
			New Person With {
				.FirstName = "Jane",
				.LastName = "Doe"
			},
			New Person With {
				.FirstName = "John",
				.LastName = "Doe"
			}
		}

		' Using Distinct with a custom equality comparer
		Dim distinctPeople = people.Distinct(New PersonEqualityComparer())

		' Display distinct people
		For Each person In distinctPeople
			Console.WriteLine($"{person.FirstName} {person.LastName}")
		Next person
	End Sub
End Class

Using Distinct with Value Types

You don't need to supply a custom equality comparison when using the Distinct method with value types.

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

public class DistinctValueTypeExample
{
    public static void Example()
    {
        List<int> integers = new List<int> { 1, 2, 2, 3, 4, 4, 5 };

        // Using Distinct to remove duplicates
        var distinctIntegers = integers.Distinct();

        // Display distinct integers
        foreach (var integer in distinctIntegers)
        {
            Console.WriteLine(integer);
        }
    }
}

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

public class DistinctValueTypeExample
{
    public static void Example()
    {
        List<int> integers = new List<int> { 1, 2, 2, 3, 4, 4, 5 };

        // Using Distinct to remove duplicates
        var distinctIntegers = integers.Distinct();

        // Display distinct integers
        foreach (var integer in distinctIntegers)
        {
            Console.WriteLine(integer);
        }
    }
}

Imports System
Imports System.Collections.Generic
Imports System.Linq

Public Class DistinctValueTypeExample
	Public Shared Sub Example()
		Dim integers As New List(Of Integer) From {1, 2, 2, 3, 4, 4, 5}

		' Using Distinct to remove duplicates
		Dim distinctIntegers = integers.Distinct()

		' Display distinct integers
		For Each [integer] In distinctIntegers
			Console.WriteLine([integer])
		Next [integer]
	End Sub
End Class

Using Distinct with Anonymous Types

Distinct may be used with anonymous types to remove duplicates based on particular attributes. Please refer to the following example:

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

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

public class DistinctAnonymousTypesExample
{
    public static void Example()
    {
        List<Person> people = new List<Person>
        {
            new Person { FirstName = "John", LastName = "Doe" },
            new Person { FirstName = "Jane", LastName = "Doe" },
            new Person { FirstName = "John", LastName = "Doe" }
        };

        // Using Distinct with anonymous types
        var distinctPeople = people
            .Select(p => new { p.FirstName, p.LastName })
            .Distinct();

        // Display distinct anonymous types
        foreach (var person in distinctPeople)
        {
            Console.WriteLine($"{person.FirstName} {person.LastName}");
        }
    }
}

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

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

public class DistinctAnonymousTypesExample
{
    public static void Example()
    {
        List<Person> people = new List<Person>
        {
            new Person { FirstName = "John", LastName = "Doe" },
            new Person { FirstName = "Jane", LastName = "Doe" },
            new Person { FirstName = "John", LastName = "Doe" }
        };

        // Using Distinct with anonymous types
        var distinctPeople = people
            .Select(p => new { p.FirstName, p.LastName })
            .Distinct();

        // Display distinct anonymous types
        foreach (var person in distinctPeople)
        {
            Console.WriteLine($"{person.FirstName} {person.LastName}");
        }
    }
}

Imports System
Imports System.Collections.Generic
Imports System.Linq

Public Class Person
	Public Property FirstName() As String
	Public Property LastName() As String
End Class

Public Class DistinctAnonymousTypesExample
	Public Shared Sub Example()
		Dim people As New List(Of Person) From {
			New Person With {
				.FirstName = "John",
				.LastName = "Doe"
			},
			New Person With {
				.FirstName = "Jane",
				.LastName = "Doe"
			},
			New Person With {
				.FirstName = "John",
				.LastName = "Doe"
			}
		}

		' Using Distinct with anonymous types
		Dim distinctPeople = people.Select(Function(p) New With {
			Key p.FirstName,
			Key p.LastName
		}).Distinct()

		' Display distinct anonymous types
		For Each person In distinctPeople
			Console.WriteLine($"{person.FirstName} {person.LastName}")
		Next person
	End Sub
End Class

Distinct by a Specific Property

When working with objects, you may either create your logic for distinguishing by a certain attribute, or you can utilize the DistinctBy extension method from third-party libraries (like MoreLINQ).

// Ensure to include the MoreLINQ Library
using MoreLinq;
using System;
using System.Collections.Generic;
using System.Linq;

public class Person
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

public class DistinctByExample
{
    public static void Example()
    {
        List<Person> people = new List<Person>
        {
            new Person { Id = 1, FirstName = "John", LastName = "Doe" },
            new Person { Id = 2, FirstName = "Jane", LastName = "Doe" },
            new Person { Id = 1, FirstName = "John", LastName = "Doe" }
        };

        // Using DistinctBy to filter distinct people by Id
        var distinctPeople = people.DistinctBy(p => p.Id);

        // Display distinct people
        foreach (var person in distinctPeople)
        {
            Console.WriteLine($"{person.Id}: {person.FirstName} {person.LastName}");
        }
    }
}

// Ensure to include the MoreLINQ Library
using MoreLinq;
using System;
using System.Collections.Generic;
using System.Linq;

public class Person
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

public class DistinctByExample
{
    public static void Example()
    {
        List<Person> people = new List<Person>
        {
            new Person { Id = 1, FirstName = "John", LastName = "Doe" },
            new Person { Id = 2, FirstName = "Jane", LastName = "Doe" },
            new Person { Id = 1, FirstName = "John", LastName = "Doe" }
        };

        // Using DistinctBy to filter distinct people by Id
        var distinctPeople = people.DistinctBy(p => p.Id);

        // Display distinct people
        foreach (var person in distinctPeople)
        {
            Console.WriteLine($"{person.Id}: {person.FirstName} {person.LastName}");
        }
    }
}

' Ensure to include the MoreLINQ Library
Imports MoreLinq
Imports System
Imports System.Collections.Generic
Imports System.Linq

Public Class Person
	Public Property Id() As Integer
	Public Property FirstName() As String
	Public Property LastName() As String
End Class

Public Class DistinctByExample
	Public Shared Sub Example()
		Dim people As New List(Of Person) From {
			New Person With {
				.Id = 1,
				.FirstName = "John",
				.LastName = "Doe"
			},
			New Person With {
				.Id = 2,
				.FirstName = "Jane",
				.LastName = "Doe"
			},
			New Person With {
				.Id = 1,
				.FirstName = "John",
				.LastName = "Doe"
			}
		}

		' Using DistinctBy to filter distinct people by Id
		Dim distinctPeople = people.DistinctBy(Function(p) p.Id)

		' Display distinct people
		For Each person In distinctPeople
			Console.WriteLine($"{person.Id}: {person.FirstName} {person.LastName}")
		Next person
	End Sub
End Class

IronPDF

Programmers may create, edit, and alter PDF documents using the C# language with the aid of the .NET library IronPDF Website. The program provides a range of tools and functionalities to enable various tasks involving PDF files, such as generating PDFs from HTML, converting HTML to PDF, merging or splitting PDF documents, and adding text, images, and annotations to already existing PDFs. To know more about IronPDF, please refer to their IronPDF Documentation.

The main feature of IronPDF is HTML to PDF Conversion, which keeps your layouts and styles intact. You can generate PDFs from web content, perfect for reports, invoices, and documentation. It supports converting HTML files, URLs, and HTML strings to PDF files.

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

• Convert HTML to PDF: You may use IronPDF to convert any kind of HTML data—including files, URLs, and strings of HTML code—into PDF documents.
• PDF Generation: Text, images, and other elements may be programmatically added to PDF documents using the C# programming language.
• PDF Manipulation: IronPDF can split a PDF file into many files, merge several PDF documents into one file, and edit PDFs that already exist.
• PDF Forms: The library enables users to build and fill PDF forms, making it useful in scenarios where form data needs to be gathered and processed.
• Security Features: IronPDF may be used to encrypt PDF documents and provide password and permission protection.
• Text Extraction: Text from PDF files may be extracted using IronPDF.

Install IronPDF

Get the IronPDF library; it's needed for setting up your project. Enter the following code into the NuGet Package Manager Console to accomplish this:

Install-Package IronPdf

Using the NuGet Package Manager to search for the package "IronPDF" is an additional choice. We may choose and download the necessary package from this list out of all the NuGet packages associated with IronPDF.

LINQ With IronPDF

Consider a situation in which you have a set of data and you wish to create various PDF documents according to different values in that set. This is where the usefulness of LINQ's Distinct shines, particularly when used with IronPDF to create documents quickly.

Generating Distinct PDFs with LINQ and IronPDF

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

public class DocumentGenerator
{
    public static void Main()
    {
        // Sample data representing categories
        List<string> categories = new List<string>
        {
            "Technology",
            "Business",
            "Health",
            "Technology",
            "Science",
            "Business",
            "Health"
        };

        // Use LINQ Distinct to filter out duplicate values
        var distinctCategories = categories.Distinct();

        // Generate a distinct elements PDF document for each category
        foreach (var category in distinctCategories)
        {
            GeneratePdfDocument(category);
        }
    }

    private static void GeneratePdfDocument(string category)
    {
        // Create a new PDF document using IronPDF
        IronPdf.HtmlToPdf renderer = new IronPdf.HtmlToPdf();
        PdfDocument pdf = renderer.RenderHtmlAsPdf($"<h1>{category} Report</h1>");

        // Save the PDF to a file
        string pdfFilePath = $"{category}_Report.pdf";
        pdf.SaveAs(pdfFilePath);

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

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

public class DocumentGenerator
{
    public static void Main()
    {
        // Sample data representing categories
        List<string> categories = new List<string>
        {
            "Technology",
            "Business",
            "Health",
            "Technology",
            "Science",
            "Business",
            "Health"
        };

        // Use LINQ Distinct to filter out duplicate values
        var distinctCategories = categories.Distinct();

        // Generate a distinct elements PDF document for each category
        foreach (var category in distinctCategories)
        {
            GeneratePdfDocument(category);
        }
    }

    private static void GeneratePdfDocument(string category)
    {
        // Create a new PDF document using IronPDF
        IronPdf.HtmlToPdf renderer = new IronPdf.HtmlToPdf();
        PdfDocument pdf = renderer.RenderHtmlAsPdf($"<h1>{category} Report</h1>");

        // Save the PDF to a file
        string pdfFilePath = $"{category}_Report.pdf";
        pdf.SaveAs(pdfFilePath);

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

Imports IronPdf
Imports System
Imports System.Collections.Generic
Imports System.Linq

Public Class DocumentGenerator
	Public Shared Sub Main()
		' Sample data representing categories
		Dim categories As New List(Of String) From {"Technology", "Business", "Health", "Technology", "Science", "Business", "Health"}

		' Use LINQ Distinct to filter out duplicate values
		Dim distinctCategories = categories.Distinct()

		' Generate a distinct elements PDF document for each category
		For Each category In distinctCategories
			GeneratePdfDocument(category)
		Next category
	End Sub

	Private Shared Sub GeneratePdfDocument(ByVal category As String)
		' Create a new PDF document using IronPDF
		Dim renderer As New IronPdf.HtmlToPdf()
		Dim pdf As PdfDocument = renderer.RenderHtmlAsPdf($"<h1>{category} Report</h1>")

		' Save the PDF to a file
		Dim pdfFilePath As String = $"{category}_Report.pdf"
		pdf.SaveAs(pdfFilePath)

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

In this example, a series of distinct categories are obtained by using the Distinct method for the categories collection. It helps to remove duplicate elements from a sequence. Next, IronPDF is used to create a PDF document with these unique elements. This method guarantees that separate PDF documents are produced solely for unique categories.

Console OUTPUT

Generated PDF Output

To know more about the IronPDF code example for generating PDFs using HTML refer to the IronPDF HTML to PDF Example Code.

Conclusion

LINQ's Distinct extension method in conjunction with IronPDF offers a robust and efficient mechanism for creating unique PDF documents based on values. This method streamlines the code and guarantees effective document production whether you are working with categories, tags, or any other data where separate documents are needed.

You may develop a reliable and expressive solution for managing different aspects of your C# applications by utilizing LINQ for data processing and IronPDF for document production. When using these strategies for your projects, keep in mind the particular needs of your application and adjust the implementation to achieve maximum dependability and performance.