At Davis R Users’ Group yesteray, Steve Culman gave us an introduction to the plyr package and how to use it to manipulate data. Here’s his presentation, and the accompanying demonstration script:
Steve’s talk is based on this paper by Hadley Wickham in the Journal of Statistical Software. A lot of useful related resources are at Hadley Wickham’s plyr website.
We had a quick exchange about using plyr for parallel processing. More on that was discussed on the listserv here