What are some examples of using GroupBy in C# LINQ?

Can you explain how to use GroupBy in C# LINQ with some examples?

Sure! The GroupBy method in LINQ is used to group elements that share a common attribute. For example, if you have a list of students and you want to group them by their grades, you can do it like this:

var students = new List<Student>
{
    new Student { Name = "Alice", Grade = "A" },
    new Student { Name = "Bob", Grade = "B" },
    new Student { Name = "Charlie", Grade = "A" }
};

var groupedStudents = students.GroupBy(s => s.Grade);

This will create groups of students based on their grades.

Can you show me how to iterate over the grouped results?

Absolutely! You can iterate over the grouped results like this:

foreach (var group in groupedStudents)
{
    Console.WriteLine($"Grade: {group.Key}");
    foreach (var student in group)
    {
        Console.WriteLine($" - {student.Name}");
    }
}

This will print each grade and the names of the students in that grade.

What if I want to count the number of students in each group?

You can use the Count method on each group to get the number of students. Here's how:

foreach (var group in groupedStudents)
{
    Console.WriteLine($"Grade: {group.Key}, Count: {group.Count()}");
}

This will display the grade along with the count of students in each group.