Matt, This is fantastic! Eight more reasons to rely on data.table for my daily research tasks. Thanks so much for your efforts.
--Mel. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Matthew Dowle Sent: Thursday, February 10, 2011 8:00 PM To: [email protected] Subject: [datatable-help] v1.5.3 has just been pushed to CRAN NEW FEATURES o .SD no longer includes 'by' columns, FR#978. This resolves the long standing annoyance of duplicated 'by' columns when the j expression returns a subset of rows from .SD. For example, the following query no longer contains a redundant 'colA.1' duplicate. DT[,.SD[2],by=colA] # 2nd row of each group Any existing code that uses .SD may require simple changes to remove workarounds. o 'by' may now be a character vector of column names. This allows syntax such as DT[,sum(x),by=key(DT)]. o X[Y] now includes Y's non-join columns, as most users naturally expect, FR#746. Please do use j in one step (i.e. X[Y,j]) since that merges just the columns j uses and is much more efficient than X[Y][,j] or merge(X,Y)[,j]. o The 'Join Inherited Scope' feature is back on, FR#1095. This is consistent with X[Y] including Y's non-join columns, enabling natural progression from X[Y] to X[Y,j]. j sees columns in X first then Y. If the same column name exists in both X and Y, the data in Y can be accessed via a prefix "i." (not yet implemented). o Ad hoc by now coerces double to integer (provided they are all.equal) and character to factor, FR#1051, as setkey already does. USER-VISIBLE CHANGES o The default for mult is now "all", as planned and prior notice given in FAQ 2.2. o ?[.data.table has been merged into ?data.table and updated, simplified, corrected and formatted. DEPRECATED & DEFUNCT o The DT() alias is now fully deprecated, as warned in NEWS for v1.4, and FAQs 2.6 and 2.7. _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
