Thanks a lot, guys. Gabor's and Mike's suggestion worked. Duncan's did not do exactly what I expected (I guess it's the "paste" in Mike's that makes "table" work as I needed it).
One more question - is there a convenient way to order the group by results as follows: As rows: the unique combinations of factors f1, f2, f3, as columns the unique values of f4. The counts are basically the same as of the GROUP BY statement (or the paste and table combination suggested by Mike). Only the way the result is structured is different. Thanks, Nick Nick Angelou wrote: > > Hi, > > I have the following table data: > > f1, f2, f3, f4. > > I want to compute the counts of unique combinations of f1-f4. In SQL I > would just write: > > SELECT COUNT(*) FROM <table> GROUP BY f1, f2, ..,f4. > > How to do this in R? > > Thanks, > > Nick > -- View this message in context: http://www.nabble.com/Group-by-in-R-tp23020587p23020963.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
