How to learn R as a programming language

I would rather suggest a good and comprehensive start, like The R Book by Michael Crawley. It's an easy-to-read and complete book on R core functions, with statistical tips and a few exercises. It focuses a lot on R strengths (e.g. linear models) and gives also useful coding tricks. It helped me a lot while I was struggling on cryptic online courses.

A good book for learning R-as-a-programming-language (as opposed to R-for-statistics) is The Art of R Programming, by Norman Matloff.

It's very readable, doesn't assume you're a computer scientist, and is quite inexpensive as R books go.

For starters, you might want to look at this article by John Cook. Also make sure that you read "The R Inferno".

There are many good resources on the R homepage, but in particular, read "An Introduction to R" and "The R Language Definition".

Some very closely related stackoverflow questions:

• books-for-learning-the-r-language.
• what-are-some-good-books-web-resources-and-projects-for-learning-r
• suggestions-on-way-resources-to-start-learning-statistical-language-r

My favorite book on the subject: "Software for Data Analysis: Programming with R", by John Chambers, the creator of the S language.