Here is a summary of the apply family of functions: http://nsaunders.wordpress.com/2010/08/20/a-brief-introduction-to-apply-in-r/ http://nsaunders.wordpress.com

Here is a summary of the apply family of functions: http://nsaunders.wordpress.com/2010/08/20/a-brief-introduction-to-apply-in-r/ http://nsaunders.wordpress.com/2010/08/20/a-brief-introducti... These are very simple functions and I generally try to use them before moving on to plyr. The are easy to set up, understand, and faster. Obviously they cannot do everything, though, which is why there is plyr.