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LINQ Distinct() Method

In this article, we will discuss how to return unique elements through the LINQ Count() function in List data structure.

Language Integrated Query language (LINQ) is used to perform operations on the C# collections or Normal data structures.

LINQ Distinct()

Distinct() in LINQ is used to return the unique values present in a data structure (List). If there are any similar values, then those will be removed.

It is possible to use this method in two ways. Let’s look into it.

Approach 1: Using Method

We will use the normal Distinct() method to return distinct values.

Syntax:

list.Distinct()

Where list is the List object created.

Approach 2: Using Query

We will use the Query similar to SQL expression that returns the unique values.

Syntax:

from i in list select i.Distinct()

Where list is the List object created and iterator iterates the elements in a list..

Example 1:

Here, we will create a list that holds integer elements and we will use Distinct() to return only the unique values.

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

 //create a class - Linuxhint
class Linuxhint
{

    static public  void Main(){

       //create data
       List first_list = new List() {23,23,45,67,89,10,10,22,23,45};


       Console.WriteLine("List: ");
           foreach (var values in first_list)
            {
                Console.WriteLine(values);
            }


        //get the unique elements from the list
       var result = first_list.Distinct();

        Console.WriteLine("Unique values from the list: ");

        foreach (var values in result)
            {
                Console.WriteLine(values);
            }

}
}

Output:

Explanation:

So first, we created a list data structure with 10 integers that include duplicates.

After that, we applied Distinct() to get the unique elements.

Finally, we can display the result using a foreach loop.

Example 2:

Here, we will create a list that holds string elements and we will use Distinct() to return only the unique values.

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

 //create a class - Linuxhint
class Linuxhint
{

    static public  void Main(){

       //create data
       List first_list = new List() {"linuxhint","linuxhint","sravan","vignan","java","java"};


       Console.WriteLine("List: ");
           foreach (var values in first_list)
            {
                Console.WriteLine(values);
            }


        //get the unique elements from the list
       var result = first_list.Distinct();

        Console.WriteLine("Unique strings from the list: ");

        foreach (var values in result)
            {
                Console.WriteLine(values);
            }

}
}

Output:

Explanation:

So first, we created a list data structure with 6 strings that include duplicates.

After that, we applied Distinct() to get the unique elements.

Finally, we can display the result using a foreach loop.

Example 3:

Here, we will create a list that holds integer elements and we will use Distinct() with Query to return only the unique values.

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

 //create a class - Linuxhint
class Linuxhint
{

    static public  void Main(){

       //create data
       List first_list = new List() {100,200,300,200,300};


       Console.WriteLine("List: ");
           foreach (var values in first_list)
            {
                Console.WriteLine(values);
            }


        //get the unique elements from the list
       var result = (from i in first_list select i).Distinct();

        Console.WriteLine("Unique values from the list: ");

        foreach (var values in result)
            {
                Console.WriteLine(values);
            }

}
}

Output:

Explanation:

So first, we created a list data structure with 10 integers that include duplicates.

After that, we applied Distinct() to get the unique elements.

Finally, we can display the result using a foreach loop.

Conclusion

Distinct() in LINQ is used to return the unique values present in a data structure. There are two ways to use the LINQ Distinct() method. We discussed three different examples with different data types. Make sure that use has to include – using System.Linq and using System.Collections.Generic command lines in your code.

About the author

Gottumukkala Sravan Kumar

B tech-hon's in Information Technology; Known programming languages - Python, R , PHP MySQL; Published 500+ articles on computer science domain