Set Operators In LINQ: Everything You Need To Know

One of the key functionalities offered by LINQ is the ability to perform set operations on collections, such as union, intersection, and difference. These set operators allow developers to combine, compare, and manipulate data in a concise and efficient manner. In this article, we will explore the different set operators available in LINQ using C#.

Set Operators in LINQ Using C#

Set operators are a set of LINQ methods that allow you to perform set operations on collections. These operations include:

Distinct: This method removes duplicate elements from a collection.
Except: This method returns a collection of elements that are in the first collection but not in the second collection.
Intersect: This method returns a collection of elements that are in both the first and second collections.
Union: This method returns a collection of elements that are in either the first or second collection.

To use a set operator, you can use the following syntax:


var result = from collection in sourceCollection
where condition
select operator(collection);

var result = from collection in sourceCollection

where condition

select operator(collection);

For example, the following code uses the Distinct() method to remove duplicate elements from a collection of strings:


var strings = new string[] { "a", "b", "a", "c", "b" };
var distinctStrings = strings.Distinct();

foreach (var string in distinctStrings)
{
    Console.WriteLine(string);
}

var strings = new string[] { "a", "b", "a", "c", "b" };

var distinctStrings = strings.Distinct();

foreach (var string in distinctStrings)

{

Console.WriteLine(string);

}

The Except() method can be used to find the elements that are in the first collection but not in the second collection. For example, the following code uses the Except() method to find the countries that are in the countries collection but not in the europeanCountries collection:


var countries = new string[] { "United States", "Canada", "Mexico", "Brazil", "Argentina" };
var europeanCountries = new string[] { "France", "Germany", "Italy", "Spain", "United Kingdom" };

var countriesInAmerica = countries.Except(europeanCountries);

foreach (var country in countriesInAmerica)
{
    Console.WriteLine(country);
}

var countries = new string[] { "United States", "Canada", "Mexico", "Brazil", "Argentina" };

var europeanCountries = new string[] { "France", "Germany", "Italy", "Spain", "United Kingdom" };

var countriesInAmerica = countries.Except(europeanCountries);

foreach (var country in countriesInAmerica)

{

Console.WriteLine(country);

}

The Intersect() method can be used to find the elements that are in both the first and second collections. For example, the following code uses the Intersect() method to find the countries that are in both the countries and europeanCountries collections:


var countries = new string[] { "United States", "Canada", "Mexico", "Brazil", "Argentina" };
var europeanCountries = new string[] { "France", "Germany", "Italy", "Spain", "United Kingdom" };

var countriesInBoth = countries.Intersect(europeanCountries);

foreach (var country in countriesInBoth)
{
   Console.WriteLine(country);
}

var countries = new string[] { "United States", "Canada", "Mexico", "Brazil", "Argentina" };

var europeanCountries = new string[] { "France", "Germany", "Italy", "Spain", "United Kingdom" };

var countriesInBoth = countries.Intersect(europeanCountries);

foreach (var country in countriesInBoth)

{

Console.WriteLine(country);

}

The Union() method can be used to find the elements that are in either the first or second collection. For example, the following code uses the Union() method to find all of the countries in the countries and europeanCountries collections:


var countries = new string[] { "United States", "Canada", "Mexico", "Brazil", "Argentina" };
var europeanCountries = new string[] { "France", "Germany", "Italy", "Spain", "United Kingdom" };

var allCountries = countries.Union(europeanCountries);

foreach (var country in allCountries)
{
    Console.WriteLine(country);
}

var countries = new string[] { "United States", "Canada", "Mexico", "Brazil", "Argentina" };

var europeanCountries = new string[] { "France", "Germany", "Italy", "Spain", "United Kingdom" };

var allCountries = countries.Union(europeanCountries);

foreach (var country in allCountries)

{

Console.WriteLine(country);

}

Using these set operators in LINQ, developers can efficiently manipulate and compare collections based on set principles. The examples provided demonstrate the basic usage of these operators, but they can be applied to more complex scenarios with custom objects and data types.