thank you very much,
all the solutions work.
Regards,
Copex


Peter Dalgaard <p.dalgaard@biostat.ku.dk> wrote:
Spencer Graves writes:

> Does the following do what you want: > x<-c(1,2,3,4,5,6,7,8,9,10)
> > y<-c(1.3,2.5,4.6,5.3,5.9,6.7,7.4,8.5,9.4,10.4)
> > erry<-c(0.2,0.3,0.2,0.1,0.4,0.2,0.3,0.4,0.3,0.2)
> >
> > plot(x, y)
> >
> > n <- length(x)
> > Y <- array(c(y-erry, y+erry), dim=c(n,2))
> > for(i in 1:n)
> + lines(rep(x[i],2), Y[i,])

(Actually, segments(x,y-erry,x,y+erry) would be a more direct way.)

> Others may have more elegant solutions, but this is simple
> enough for me to understand AND produces essentially the same result
> in R 1.8.1 and S-Plus 6.2. hope this helps. spencer graves

There are a number of fine points to get right, though, esp. if the
bars get longer than in this example.

I think there are special "plot with errorbars" in some of the "misc"
packages on CRAN (their authors are likely to chime in any moment
now), but for a relatively simple solution, I think I'd do

plot(x, y, type="n", ylim=range(y+erry,y-erry))
arrows(x,y-erry,x,y+erry,code=3,length=.005*diff(range(x)),angle=90)
points(x,y,pch=21,bg="white")


-- 
O__ ---- Peter Dalgaard Blegdamsvej 3 
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N 
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907


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