LINQ Set Operators

In LINQ, set operators are used to perform operations that involve comparing and combining sequences of data. They are useful for tasks like finding unique elements, checking for overlaps, or combining results from multiple sequences. There are following Set operators.

1. Distinct
2. Union
3. Intersect
4. Except
5. Concat
6. Zip

1. Distinct

The Distinct operator is used to remove duplicate elements from a sequence.

Example

List<int> numbers = new List<int> { 1, 2, 2, 3, 4, 4, 5 };
var distinctNumbers = numbers.Distinct();

foreach (var number in distinctNumbers)
{
    Console.WriteLine(number); // Output: 1, 2, 3, 4, 5
}

2. Union

The Union operator combines two sequences and returns a sequence of unique elements that appear in either of the sequences.

Example

List<int> numbers1 = new List<int> { 1, 2, 3, 4 };
List<int> numbers2 = new List<int> { 3, 4, 5, 6 };
var unionNumbers = numbers1.Union(numbers2);

foreach (var number in unionNumbers)
{
    Console.WriteLine(number); // Output: 1, 2, 3, 4, 5, 6
}

3. Intersect

The Intersect operator returns a sequence of elements that are present in both sequences.

Example

List<int> numbers1 = new List<int> { 1, 2, 3, 4 };
List<int> numbers2 = new List<int> { 3, 4, 5, 6 };
var intersectNumbers = numbers1.Intersect(numbers2);

foreach (var number in intersectNumbers)
{
    Console.WriteLine(number); // Output: 3, 4
}

4. Except

The Except operator returns a sequence of elements that are in the first sequence but not in the second sequence.

Example

List<int>  numbers1 = new List<int>  { 1, 2, 3, 4 };
List<int>  numbers2 = new List<int>  { 3, 4, 5, 6 };
var exceptNumbers = numbers1.Except(numbers2);

foreach (var number in exceptNumbers)
{
    Console.WriteLine(number); // Output: 1, 2
}

5. Concat

The Concat operator combines two sequences into a single sequence. Note that Concat does not remove duplicates; it simply appends one sequence to another.

Example

List<int> numbers1 = new List<int> { 1, 2, 3 };
List<int> numbers2 = new List<int> { 4, 5, 6 };
var concatenatedNumbers = numbers1.Concat(numbers2);

foreach (var number in concatenatedNumbers)
{
    Console.WriteLine(number); // Output: 1, 2, 3, 4, 5, 6
}

6. Zip

The Zip operator combines two sequences into a single sequence of pairs, using a specified function to combine corresponding elements.

Example

List<string> names = new List<string> { "Rohatash", "Mohit", "Saurav" };
List<int> ages = new List<int> { 30, 25, 40 };
var zipped = names.Zip(ages, (name, age) => new { Name = name, Age = age });

foreach (var item in zipped)
{
    Console.WriteLine($"{item.Name} is {item.Age} years old");
}
// Output:
// Rohatash is 30 years old
// Mohit is 25 years old
// Saurav is 40 years old