This is a list of significant new or updated packages that were released on CRAN this month. For a complete list of all updates, see the CRANberries archive for March 2009.
WriteXLS is a new package (a single function, actually) that writes one or more data frames to an Excel (XLS) file.
mgcv, a package for estimating Generalized Additive Models with multiple smoothing parameter selection methods, has been updated to add REML and ML smoothing selection, and the Tweedie family of distributions.
ltm, a package for Item Response Theory analysis, has been updated to implement the Generalized Partial Credit model, amongst other new features.
data.table, an enhanced version of data.frame with database-like selections and joins, has been available as a package on CRAN for some time but was only recently announced.
