Hi As you did not provide any data you probably can not get canned solution
> Hello everyone, > > I have two questions: > > 1) > > I want to create a subset of a data frame column-wise and simultaneously > extract the row names into a "proper" variable. I tried this, but received > an error: > > > myleft<-mydata[c(id=row.names(mydata),"workshop","gender","q1","q2")] > Error in `[.data.frame`(mydata, c(id = row.names(mydata), "workshop", : > undefined columns selected > Is the following the best way to go about this: > > > > myleft<-data.frame(id=row.names(mydata),mydata)[c > ("id","workshop","gender","q1","q2")] > > myleft If I understand correctly you want only some columns, all rows and make also new column identical with row names. either cbind(id=row.names(mydata),mydata[, c(2,4,5,6)]) or data.frame(id=row.names(mydata),mydata[, c(2,4,5,6)]) can do it. > > 2) > > Is it possible to merge data using merge() with a by variable that is the AFAI no. > row names? I tried this: > > > both<-merge(myleft,myright,by=row.names(myleft)) > Error in fix.by(by.x, x) : 'by' must specify valid column(s) > > both > Suggestions? Regards Petr > > > Thanks! > > Dan > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. ______________________________________________ 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.