I'm assuming that the full-stop after the 60 in the question is a typo. I'm assuming 'grade' refers to earned/possible.
Since you've said you are currently writing the code to populate the list, I would suggest using the tab character rather than the two pipe character separator. This will make the file a TSV file, and makes the code slightly easier to write. (The tab character is represented by \t in source code, either in a string, or as a character: '\t'.) If you're writing the file yourself, it would help to keep the earned & possible values together using a different separator; for example 27,30;56,60;45,70(etc). This makes it easier to separate; but I'll show solutions for both.
public class Result
{
// This constructor is used by the "different separator for Earned and Possible" approach.
// Remove this and the default constructor if you don't want to go that way.
public Result(string line)
{
var parts = line.Split(',');
if (parts.Length != 2)
{
throw new ArgumentException($"Result had {parts.Length} parts: '{line}'");
}
EarnedPoints = int.Parse(parts[0]);
PossiblePoints = int.Parse(parts[1]);
}
public Result()
{
}
// Remove this constructor if you go for the approach above.
public Result(int earnedPoints, int possiblePoints)
{
EarnedPoints = earnedPoints;
PossiblePoints = possiblePoints;
}
public int EarnedPoints { get; }
public int PossiblePoints { get; }
public double Grade => (double)EarnedPoints / PossiblePoints;
public string GradeAsPercentage => $"{Grade:P2}";
}
public class Student
{
public Student(string line)
{
var parts = line.Split(new[] { "||" }, StringSplitOptions.None);
// Could use this instead if you go for TSV: var parts = line.Split('\t');
if (parts.Length != 4)
{
throw new ArgumentException($"Student had {parts.Length} parts: '{line}'");
}
Id = parts[0];
Forenames = parts[1];
Surname = parts[2];
string remainder = parts[3];
// This is how simple it would be if you used a different separator to group the Earned and Possible together
// Results = remainder.Split(';').Select(result => new Result(result)).ToList();
// Below is an approach where commas are used for everything...
Results = new List<Result>();
var items = remainder.Split(',');
if (items.Length % 2 == 1)
{
throw new ArgumentException($"Odd number of parts in the result: '{line}'");
}
int offset = 0;
while (offset < items.Length)
{
int earnedPoints = int.Parse(items[offset++]);
int possiblePoints = int.Parse(items[offset++]);
Results.Add(new Result(earnedPoints, possiblePoints));
}
}
public string Id { get; } // Could make this an 'int', in which case use "int.Parse(parts[0])" when setting it, above
public string Forenames { get; }
public string Surname { get; }
public IList<Result> Results { get; }
public double AverageGrade => Results.Average(r => r.Grade);
public string AverageGradeAsPercentage => $"{AverageGrade:P2}";
}
then you could just do this to read in the whole file...
var students = File.ReadLines(yourFileName).Skip(1).Select(l => new Student(l));
Slight caution: I've gotta go, so rushed a few bits, but hopefully it all works.
