FasteR! HigheR! StrongeR! – A Guide to Speeding Up R Code for Busy People

Code optimization is a matter is a matter of personal taste and priorities. There may be some ways of writing code that are better or worse, and there are definitely ways that will make it run faster, but before you dive into optimization, you may read the following:

http://www.r-bloggers.com/faster-higher-stonger-a-guide-to-speeding-up-r-code-for-busy-people/