A set of tools that solves a common set of problems: you need to break a
big problem down into manageable pieces, operate on each piece and then
put all the pieces back together. For example, you might want to fit a
model to each spatial location or time point in your study, summarise data
by panels or collapse high-dimensional arrays to simpler summary
statistics. The development of plyr has been generously supported by
Becton Dickinson.
