Linq to group by two fields and average

Question

I have the following C# models:

public class RawData
{
    public int questionnaireId { get; set; }

    public int coachNodeId { get; set; }

    public int ques         


        

Answer 1

assuming you have a List called list, you are wanting:

var results = list.GroupBy(x => new
                                {
                                     questionnaire = x.questionnaireId,
                                     coach = x.coachNodeId
                                })
                  .Select(x => new AveragedData
                                {
                                     coachNodeId = x.Key.coach,
                                     questionnaireNumber = x.Key.questionnaire,
                                     averageScore = x.Average(xx => xx.score)
                                })
                  .ToList();

Do the grouping, then use a Select to project the data to your type, using LINQ's Average as well.