I have realised that I should have used "detach" before attaching another dataframe, but even when I do this it's still giving me lots of lines, rather than just one:
My code: m<-runif(1,0,1) m mres<-m*(seq(1,12)) mres ssd<-rexp(1,1) ssd devs<-rep(0,length(mres)) for(i in 1:length(mres)){devs[i]<-rnorm(1,0,ssd)} devs plot(-10,-10,xlim=c(1,24),ylim=c(0,20000)) sales<-round((mres+devs)*1000) points(sales,pch=19) ptr<-cbind(1:length(sales),sales,sales,sales) ptr sdf<-data.frame(cbind(1:nrow(ptr),sales)) sdf colnames(sdf)<-c(“monat”,“mitte”) sdf attach(sdf) s.lm<-lm(mitte~monat) s.lm abline(s.lm,lty=2) news<-data.frame(monat=nrow(sdf)+1) news fcs<-predict(s.lm,news,interval=“predict”) fcs points(1+nrow(ptr),fcs[,1],col=“grey”,pch=19) points(1+nrow(ptr),fcs[,2]) points(1+nrow(ptr),fcs[,3]) ptr<-rbind(ptr,c(1+nrow(ptr),fcs[2],fcs[1],fcs[3])) ptr highdf<-data.frame(ptr[,c(1,4)]) highdf colnames(highdf)<-c(“month”,“sales”) highdf detach(sdf) attach(highdf) h.lm<-lm(highdf[,2]~highdf[,1]) h.lm abline(h.lm,col="gray",lty=2) news<-data.frame(month=nrow(ptr)+1) news hcs<-predict(h.lm,news,interval=“predict”) hcs [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.