Closed because, as I said, the question as written is a pure R programming question as opposed to a bioinformatics research question. Nothing to do with banning discussion. If the questioner wants to make their question more relevant to this forum, happy to reopen.

Well then if discussion is still open, then I'll just add that I found the "grouping data" aspect of the question the most interesting. The idea that methods of grouping data and displaying the results is not relevant to bioinformatics research, something I do every day in my bioinformatics research, is still beyond my comprehension. Good thing realities are negotiated rather than dictated. I was also prompted to think of times when a pie chart is preferable over other methods. A recent lab meeting I attended where people spent way too much time haggling over small differences in area of a bar chart was a complete waste of time (the differences weren't meaningful). On a pie chart the subtle differences would have been obscured, thus I think pie charts can be good for making a point comparing really small slices to really big slices (i.e. good for very different areas, but not for similar areas).