Hi Uwe, I mistook the arguments for the function of arrows. I understand now. Thanks again.
2009/11/5 Uwe Ligges <lig...@statistik.tu-dortmund.de> > > > zhijie zhang wrote: > >> Hi Uwe, >> It works. Why does the following argument generate different results? >> with(data, arrows(x[-length(x)], y[-length(x)], x[-1], y[-1])) >> #correct,multiple joins >> > > In the former you select all elements of the vectors except the first or > last one, respectively. > > In the next call you select just one arguemnt of each vector, namely the > first or last one. > > Uwe Ligges > > > with(data, arrows(x[1], y[1], x[length(x)], y[length(x)])) #wrong,seems >> to >> be only one join >> From the ?arrows, the second argument should work. What is the problem? >> Thanks a lot. >> #codes: >> x<-c(1:6);y<-c(1:6);time<-c(6:1);data<-cbind(x,y,time);data >> data<-data.frame(data[order(data[,"time"]),]) >> with(data, plot(x,y)) >> with(data, arrows(x[-length(x)], y[-length(x)], x[-1], y[-1])) >> >> with(data, plot(x,y)) >> with(data, arrows(x[1], y[1], x[length(x)], y[length(x)])) >> 2009/11/4 Uwe Ligges <lig...@statistik.tu-dortmund.de> >> >> >>> zhijie zhang wrote: >>> >>> Hi, >>>> I have a data set with three variables,X Y and Time. X and Y are the >>>> coordinates of points, i want to join these points according to the Time >>>> sequence using arrows? >>>> Demo Example data: >>>> >>>> x<-c(1:6) >>>>> y<-c(1:6) >>>>> time<-c(6:1) >>>>> data<-cbind(x,y,time) >>>>> data >>>>> >>>>> x y time >>>> [1,] 1 1 6 >>>> [2,] 2 2 5 >>>> [3,] 3 3 4 >>>> [4,] 4 4 3 >>>> [5,] 5 5 2 >>>> [6,] 6 6 1 >>>> I hope to join the six points with points' time=1 as starting point and >>>> points' time=6 as endpoint. So the sequence is time=1,2,3,4,5,6 and join >>>> the >>>> corresponding points with arrows. >>>> Any ideas on it? >>>> >>>> >>> data <- data.frame(data[order(data[,"time"]),]) >>> with(data, plot(y ~ x)) >>> with(data, arrows(x[-length(x)], y[-length(x)], x[-1], y[-1])) >>> >>> >>> Uwe Ligges >>> >>> >>> [[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<http://www.r-project.org/posting-guide.html> >>>> <http://www.r-project.org/posting-guide.html> >>>> >>>> and provide commented, minimal, self-contained, reproducible code. >>>> >>>> >> [[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.
