This is the kind of thing that leads experienced R users to avoid attach for data analysis. Read "The R Inferno".
Use the "data" argument to lm, and the "newdata" argument to predict.lm. -- Sent from my phone. Please excuse my brevity. On January 31, 2018 9:20:10 AM PST, WRAY NICHOLAS via R-help <r-help@r-project.org> wrote: >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. ______________________________________________ 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.