On 27/09/2007, at 12:27 PM, ckang2 at gmail.com wrote:
> Hello, Listers
>
> I'm trying to run blloean logit model with R.
>
> My code is:
>
>> library(boolean)
>> library(foreign)
>> pr <- read.dta ("prcore1.dta")
>> bp <- boolprep ("(a&b)|c", "cwt",
a="O1", b="t", c="DM2
>> + ah + md + con + n3 + rel + slo + pyrs
>> + sp1 + sp2 + spl3")
>> answer <- boolean (bp, link = "logit", method =
"nlm")
>
> But I got an error message here as follows:
>
> Error in eval(expr, envir, enclos) : object "cwt" not found
>
> "cwt" is my D.V. and I made sure that R read the data correctly.
>
> It might be a stupid question.But, since I'm a very very beginner of
> R, I don't know what's wrong.
> I tried to figure out this with the manual, but I can't get any
> answer.
>
> Could you anyone help me out?
The variable ``cwt'' is a component of the data frame ``pr''; it
is
not lying
around loose in the workspace (global environment) where the function
boolean()
can see it. You need to tell boolean() where to find ``cwt'' and the
other variables
referred to. I don't know from the boolean package, but I conjecture
that the
boolean function has a ``data'' argument, in which case
answer <- boolean (bp, link = "logit", method =
"nlm",data=pr)
may work. Otherwise you could
(a) do:
attach(pr)
prior to the call to boolean, or
(b) use with():
answer <- with(pr, boolean (bp, link = "logit", method =
"nlm"))
cheers,
Rolf Turner
######################################################################
Attention:\ This e-mail message is privileged and confidenti...{{dropped}}