I was working with our copy editor on Appendix A of Practical Data Science with R, 2nd Edition; Zumel, Mount; Manning 2019, and ran into this little point (unfortunately) buried in the back of the book.
In our opinion the R ecosystem is the fastest path to substantial data science, statistical, and machine learning accomplishment.
This is why we use and teach R (in addition to using and teaching Python).
Data Scientist and trainer at Win Vector LLC. One of the authors of Practical Data Science with R.