I think you are getting a rounding or truncating problem in the printing Try print[lon[x])
and see what you get --- Jingru Dai <[EMAIL PROTECTED]> wrote: > Hi, everyone > > I got some problems when trying to subscript the > value of vector and > list, by using calculated indices. > Here is the vector I am generated > lon<-rep(0,886);lat<-rep(0,691) > for (i in 1:886){ > lon[i]<-112+0.05*(i-1) > } > for (i in 691:1){ > lat[i]<--44.5+0.05*(691-i) > } > For a given location of lon(xp) and lat(yp), I would > like to calculate > the position of them, and using that to get the > value for the location > from one list. > xp<-c(112,112.05); yp<-c(-10,-10.10) > > x<-rep(0,length(xp)); y<-rep(0,length(yp)) > for (i in 1:length(xp)){ > x[i]<-(xp[i]-112)/0.05+1 > } > for(j in 1:length(yp)){ > y[j]<-(-10-yp[j])/0.05+1 > } > So here the value of x and y should indicate the > position where xp and > yp are in the vector lon and lat. And it appears to > be the right > number. But when I tried to retrieve the value of > lon using the > position, it returns the wrong value. Here's the > result I got > > x > [1] 1 2 > > lon[x] > [1] 112 112 > > lon[c(1,2)] > [1] 112.00 112.05 > > y > [1] 1 3 > > lat[y] > [1] -10.00 -10.05 > > lat[c(1,3)] > [1] -10.0 -10.1 > > I have no idea why it returns the wrong value when I > subscripts by x, > while it works perfectly fine when I subscripts with > the value of x > directly. Is there any special rule of subscripts? > My version of R is > 2.5.1. > Thanks a lot > > Jingru Dai > ---- > School of Mathematical Sciences > Rm 454, Building 28 > Monash University, 3800 > Victoria, Australia > > ______________________________________________ > 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. > ______________________________________________ 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.