public void GroupByCompositeKey()

[Jrarmyjr]

public void GroupByCompositeKey()
{
var queryHighScoreGroups =
from student in students
group student by new { FirstLetter = student.LastName[0],
Score = student.ExamScores[0] > 85 } into studentGroup
orderby studentGroup.Key.FirstLetter
select studentGroup;

Console.WriteLine("\r\nGroup and order by a compound key:");
foreach (var scoreGroup in queryHighScoreGroups)
{
    string s = scoreGroup.Key.Score == true ? "more than" : "less than";
    Console.WriteLine($"Name starts with {scoreGroup.Key.FirstLetter} who scored {s} 85");
    foreach (var item in scoreGroup)
    {
        Console.WriteLine($"\t{item.FirstName} {item.LastName}");
    }
}

}

/* Output:
Group and order by a compound key:
Name starts with A who scored more than 85
Terry Adams
Name starts with F who scored more than 85
Fadi Fakhouri
Hanying Feng
Name starts with G who scored more than 85
Cesar Garcia
Hugo Garcia
Name starts with G who scored less than 85
Debra Garcia
Name starts with M who scored more than 85
Sven Mortensen
Name starts with O who scored less than 85
Claire O'Donnell
Name starts with O who scored more than 85
Svetlana Omelchenko
Name starts with T who scored less than 85
Lance Tucker
Name starts with T who scored more than 85
Michael Tucker
Name starts with Z who scored more than 85
Eugene Zabokritski
*/

Originally posted by @Jrarmyjr in https://github.com/Jrarmyjr/html/issues/1#issuecomment-891432099