I took this free course as my first real introduction to the R programming language.
I would highly recommend it for any beginner who wants a comprehensive overview of R.
You’ll be introduced to the basic syntax of R and its building blocks of vectors, matrices and data frames from absolute beginner level.
It has a built-in R environment. Each lesson usually presents a half-completed problem and instructions on how to solve it.
It has tips and if you really get stuck you can ‘cheat’ and hit the solution button.
It has paid-for additional modules, which I am taking.
As I said in What Is R?, the program has a learning curve. This course makes that curve gentler. Try it here.