This hopefully is trivial. I am trying to reshape the data using the reshape package.
First I read in the data: a2009 <- read.csv("Total2009.dat", header = TRUE) Then I trim it so that it only contains the columns that I have interested in: m2009 <- melt(a2009, id.var=c("DayOfYear","Category","SubCategory","Sku"), measure.var=c("Quantity"), na.rm=TRUE) Then I start to formulate the data that I will process: c2009 <- cast(m2009, DayOfYear ~ variable | Category, sum) Finally I aggregate the data: t2009 <- cast(m2009, DayOfYear ~ variable, sum) My question is on the third step above (repeated here) c2009 <- cast(m2009, DayOfYear ~ variable | Category, sum) This gets the data assocated with a unique 'Category' name. I want to get the data grouped by 'Category' and 'SubCategory'. The 'SubCategory' is not unique but the combination 'Category' and 'SubCategory' form a unique pair. What would be the formula that would give me the data grouped by Category AND SubCategory? Would it be as simple as: c2009 <- cast(m2009, DayOfYear ~ variable | Category & SubCategory, sum) ? Thank you for your suggestions. Kevin ______________________________________________ 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.