I just finished all of the lessons for the R Programming class on Coursera. The last two weeks that I had left taught about various *apply functions, the split function, how to debug, how to simulate data, and how to use R Profiler.
I found the swirl exercises to be the best way to learn all of these things, and I think that the programming assignments were also really good to make you think about how to go about things. Unfortunately, I didn’t pay for the class, so the fact that I completed it won’t be acknowledged. But I’m all set to take the next class in the sequence as soon as it goes live.