I think that it would help very much if you included a (small) example of the data that you want to use.
Further some suggestions:
enclosing your code in three (or four in case of Rmd chunks) backticks makes it better readable
indicate more clearly what is the error (if any) that you are encountering.
you seem to use a function sort_desc that I do not know. So this is no code that we (I) can run to see what is wrong. Try to create a reprex ! The main points for a reprex: be as clear as possible and make the problem as small as possible. For example I do not think that the fact that this is running in an Rmd environment matters (but of course I may be wrong).