I have a dataframe df with two columns x and y. I want to count the number of times a unique x, y combination occurs.
For example x<- c(1,2,3,4,5,1,2,3,4) y<- c(1,2,3,4,5,1,2,4,1) df<-as.data.frame(cbind(x, y)) #what is the correct way to use ddply for this example? ddply(df, c('x','y', summarize, ??) #desired output -- format and order doesn't matter # (x, y) count #-------------------- # (1, 1) 2 # (2, 2) 2 # (3, 3) 1 # (4, 4) 1 # (5, 5) 1 # (2, 3) 1 # (3, 4) 1 # (4, 1) 1 [[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.