R help - Nov 2007 - R 2.6 and library(survival)

Hi all,

I have installed in R 2.6 the survival package and I am trying to analyze some 
data and present plots. The problem occurs when I try to plot lines on 
the same plot. E.g. take simulated data for time (t), event (e) and groups 
(group1 and group2) and do:
 
### this is how I create the plots
plot1<-survfit(Surv(t,e)~ as.factor(group1))
plot2<-survfit(Surv(t,e)~ as.factor(group2))

plot(plot1)
lines(plot2,type="s")
   Error in rep(2, n2 - 1) : invalid 'times' argument

The plot is created (plot1) but the lines (plot2) are not. I have run this same
program
several times from my previous pc (R 2.4 was installed)and I never had such a
problem.
Now suddenly this error message appears and it concerns only the survival
package (I mean
for simple plots there is no problem to plot lines in an existing plot). Is
there a problem
with R 2.6 on this matter? Can someone please help?


Thank you,
Makis

makis motakis-2 wrote:
> 
> Hi all,
> 
> I have installed in R 2.6 the survival package and I am trying to analyze
> some 
> data and present plots. The problem occurs when I try to plot lines on 
> the same plot. E.g. take simulated data for time (t), event (e) and groups 
> (group1 and group2) and do:
>  
> ### this is how I create the plots
> plot1<-survfit(Surv(t,e)~ as.factor(group1))
> plot2<-survfit(Surv(t,e)~ as.factor(group2))
> 
> plot(plot1)
> lines(plot2,type="s")
>    Error in rep(2, n2 - 1) : invalid 'times' argument
> 
> The plot is created (plot1) but the lines (plot2) are not. I have run this
> same program 
> several times from my previous pc (R 2.4 was installed)and I never had
> such a problem. 
> Now suddenly this error message appears and it concerns only the survival
> package (I mean 
> for simple plots there is no problem to plot lines in an existing plot).
> Is there a problem 
> with R 2.6 on this matter? Can someone please help?
> 
> 
Don't know ... a simple reproducible example would help ...

(Some really really trivial things I tried worked, for example:

z = rexp(100)
f1 = factor(rep(1:5,each=20))
f2 = factor(rep(1:2,each=50))
event = rep(1,100)
library(survival)
s1 = survfit(Surv(z,event)~f1)
s2 = survfit(Surv(z,event)~f2)
plot(s1)
lines(s2,col=2,type="s")
> sessionInfo()
R version 2.6.0 (2007-10-03) 
i486-pc-linux-gnu 

locale:
LC_CTYPE=en_US.UTF-8;LC_NUMERIC=C;LC_TIME=en_US.UTF-8;LC_COLLATE=en_US.UTF-8;LC_MONETARY=en_US.UTF-8;LC_MESSAGES=en_US.UTF-8;LC_PAPER=en_US.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US.UTF-8;LC_IDENTIFICATION=C

attached base packages:
[1] splines   stats     graphics  grDevices utils     datasets  methods  
[8] base     

other attached packages:
[1] survival_2.34

  Ben Bolker

-- 
View this message in context:
http://www.nabble.com/R-2.6-and-library%28survival%29-tf4859847.html#a13932498
Sent from the R help mailing list archive at Nabble.com.