Reshape2 is a reboot of the reshape package. It's been over five years since the first release of the package, and in that time I've learned a tremendous amount about R programming, and how to work with data in R. Reshape2 uses that knowledge to make a new package for reshaping data that is much more focussed and much much faster. This version improves speed at the cost of functionality, so I have renamed it to `reshape2` to avoid causing problems for existing users. Based on user feedback I may reintroduce some of these features. What's new in `reshape2`: * considerably faster and more memory efficient thanks to a much better underlying algorithm that uses the power and speed of subsetting to the fullest extent, in most cases only making a single copy of the data. * cast is replaced by two functions depending on the output type: `dcast` produces data frames, and `acast` produces matrices/arrays. * multidimensional margins are now possible: `grand_row` and `grand_col` have been dropped: now the name of the margin refers to the variable that has its value set to (all). * some features have been removed such as the `|` cast operator, and the ability to return multiple values from an aggregation function. I'm reasonably sure both these operations are better performed by plyr. * a new cast syntax which allows you to reshape based on functions of variables (based on the same underlying syntax as plyr): * better development practices like namespaces and tests. Initial benchmarking has shown `melt` to be up to 10x faster, pure reshaping `cast` up to 100x faster, and aggregating `cast()` up to 10x faster. This work has been generously supported by BD (Becton Dickinson). Version 1.1 ----------- * `melt.data.frame` no longer turns characters into factors * All melt methods gain a `na.rm` and `value.name` arguments - these previously were only possessed by `melt.data.frame` (Fixes #5) -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ _______________________________________________ R-packages mailing list R-packages at r-project.org https://stat.ethz.ch/mailman/listinfo/r-packages