[R] subset and lme

[Sundar Dorai-Raj]

Todd Ogden wrote:

> I'm puzzled by the following problem, which appears when 
> attempting to run an analysis on part of a dataset:
> 
> If I try:
> 
>   csubset <- dat$Diagnosis==0
>   cont <- lme(fixed=cform,
>                    random = ~1|StudyName,
>                       data=dat,subset=csubset,na.action=na.omit)
> 
> Then I get:
> 
> Error in eval(expr, envir, enclos) : Object "csubset" not found
> 
> But if I do instead:
> 
>   cdat <- dat[dat$Diagnosis==0,]
>   cont <- lme(fixed=cform,
>                    random = ~1|StudyName,
>                       data=cdat,na.action=na.omit)
> 
> Then everything is fine.
> 
> I'm puzzled that the object can't be found.  Maybe I'm 
> overlooking something obvious?
> 

Todd,
   What version of R/nlme? I just tried the following:

library(nlme)
data(Orthodont)
csubset <- Orthodont$Sex == "Male"
fm1 <- lme(distance ~ age, data = Orthodont,
            random = ~ 1, subset = csubset)
fm2 <- lme(distance ~ age, data = Orthodont,
            random = ~ 1, subset = Sex == "Male")
fm3 <- lme(distance ~ age, data = Orthodont[csubset, ],
            random = ~ 1)

 > R.version.string
[1] "R version 1.9.0, 2004-05-06"
R> library(help = "nlme")

		Information on Package 'nlme'

Description:

Package: nlme
Version: 3.1-48
Date: 2004/01/14
<snip>

--sundar