I have two nested data frames: a<-rnorm(6) b<-rnorm(9) f1<-c("x1","x2","x3")) f2<-c("y1","y2") id<-c(1:6) a_df<-data.frame(cbind(id,f1,"y1",a)) id<-c(1:9) b_df<-data.frame(cbind(id,f1,"y2",b))
I want to preserve id and f1, but want to collapse f2 and take the corresponding mean values of a and b. Missing value in either dataframe should be handled properly (i.e., just take the non-missing number without dividing by 2). I had a look at rowSum/Means and s/l/tapply, but couldn't figure out how to handle this case cleanly. Any suggestions? Thanks Gordon ______________________________________________ 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.