Hello! I'm trying to runs stats on two vars at a time in a big data frame. I knew how to do this in SAS many years ago, but have half-forgotten that as well!
I need, for instance, mean(value) by x-y combination: x y z value 1 1 1 10 1 1 2 20 1 2 1 30 with results: x y mean(value) 1 1 15 1 2 30 Any help? Thanks, ~Zack -- View this message in context: http://old.nabble.com/By-processing-on-two-variables-at-once--tp26312115p26312115.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.
