plyr refers to a set of tools for splitting, applying and combining data in R.
plyr refers to a set of tools for splitting, applying and combining data. It solves a common set of problems: the user needs to break a big problem down into manageable pieces, operate on each piece, and then put all the pieces back together. For example, the user might want to fit a model to each spatial location or time point in the study, summarize data by panels, or collapse high-dimensional arrays to simpler summary statistics.
