C#

I found an Unexplainable behaviour of LINQ in a tutorial code example from this site:

How to: Populate Object Collections from Multiple Sources (LINQ) (C#)
https://docs.microsoft.com/en-us/dotnet/articles/csharp/programming-guide/concepts/linq/how-to-populate-object-collections-from-multiple-sources-linq

How to: Join Content from   
        // Dissimilar Files (LINQ).  

names.csv
-----------------------------------
Omelchenko,Svetlana,111  
O'Donnell,Claire,112  
Mortensen,Sven,113  
Garcia,Cesar,114  
Garcia,Debra,115  
Fakhouri,Fadi,116  
Feng,Hanying,117  
Garcia,Hugo,118  
Tucker,Lance,119  
Adams,Terry,120  
Zabokritski,Eugene,121  
Tucker,Michael,122  

scores.csv
-----------------------------------
111, 97, 92, 81, 60  
112, 75, 84, 91, 39  
113, 88, 94, 65, 91  
114, 97, 89, 85, 82  
115, 35, 72, 91, 70  
116, 99, 86, 90, 94  
117, 93, 92, 80, 87  
118, 92, 90, 83, 78  
119, 68, 79, 88, 92  
120, 99, 82, 81, 79  
121, 96, 85, 91, 60  
122, 94, 92, 91, 91   

Code:

class Student  
{  
    public string FirstName { get; set; }  
    public string LastName { get; set; }  
    public int ID { get; set; }  
    public List<int> ExamScores { get; set; }  
}


//…

public static void Main()  
{
 
 	 
 	 string filepathname = @"C:\LINQPad\";  
	 string[] names = System.IO.File.ReadAllLines(filepathname + "names.csv");  
 
	 string[] scores = System.IO.File.ReadAllLines(filepathname + "scores.csv");       

        IEnumerable<Student> queryNamesScores =  
            from nameLine in names  
            let splitName = nameLine.Split(',')  
            from scoreLine in scores  
            let splitScoreLine = scoreLine.Split(',')  
            where splitName[2] == splitScoreLine[0]  // no match??			
            select new Student()  
            {  
                FirstName = splitName[0],  
                LastName = splitName[1],  
                ID = Convert.ToInt32(splitName[2]),  
                ExamScores = (from scoreAsText in splitScoreLine.Skip(1)  
                              select Convert.ToInt32(scoreAsText)).  
                              ToList()  
            };         
  
        List<Student> students = queryNamesScores.ToList();  

        // Display each student's name and exam score average.  
        foreach (var student in students)  
        {  
            Console.WriteLine("The average score of {0} {1} is {2}.",  
                student.FirstName, student.LastName,  
                student.ExamScores.Average());  
        } 
 
 }

 Expected Output:   
    The average score of Omelchenko Svetlana is 82.5.  
    The average score of O'Donnell Claire is 72.25.  
    The average score of Mortensen Sven is 84.5.  
    The average score of Garcia Cesar is 88.25.  
    The average score of Garcia Debra is 67.  
    The average score of Fakhouri Fadi is 92.25.  
    The average score of Feng Hanying is 88.  
    The average score of Garcia Hugo is 85.75.  
    The average score of Tucker Lance is 81.75.  
    The average score of Adams Terry is 85.25.  
    The average score of Zabokritski Eugene is 83.  
    The average score of Tucker Michael is 92.  
*/

* Real Output:  
    … nothing ….
*/

Why does LINQ not match correctly 
At this point of code:

where splitName[2] == splitScoreLine[0]  // no match??		

And therefore no output will be generated

Thanks for advice

Alberto