Thanks a lot, Jeremy!
Both options look really neat and now I have to decide which one I like better. 🙂
The issue with the csv file was to find out that it was the actual formatting that caused the error and not something in my code. I got suspicious after a while, when I remembered that when I read my csv files into R, I have to change the delimiter setting as well. After some researching, it turns out that Germany (and probably some other European countries as well) uses the comma to indicate the decimal, so the Windows setting for the default separator is the semicolon. Small difference, big huuuuh???
So, good to know that tsv files are also accepted by PennController.