[R] obtain names of variables and data from glm object

[Gabor Grothendieck]

Try this:

g <- glm(demand ~ Time, BOD, family = gaussian)
all.vars(formula(g))

The result will be a character vector whose 1st component is
the name of the response and whose subsequent components
are the names of the predictor variables.

On Sun, Jul 26, 2009 at 3:14 PM, Jacob Wegelin<jacob.wegelin at gmail.com> wrote:
> Suppose we have some glm object such as:
>
> myglm <- glm( y ~ x, data=DAT)
>
> Is there an elegant way--or the "right way" within the R way of thinking--to
> obtain the names of the response variable, the predictor variables, and the
> dataset, as character strings?
>
> For instance, suppose the "right way" was to use the (currently fictitious)
> functions theresponse(), thepredictors(), and theDataSet().  Then I would be
> able to write a function that obtains the names and subsequently pastes text
> along the following lines:
>
> theResponse <- theresponse( myglm )
>
> theFirstPredictor <- thepredictors( myglm )[1]
>
> theDataSet <- theDataSet(myglm)
>
> title(main= paste(theResponse, " is the response and ", theFirstPredictor, "
> is the only predictor")
>
> In reality, I can of course extract
>
>> formula(myglm)
> y ~ x
>
> but I see no elegant way to extract the names of the predictor and response
> from this object. The deparse() function doesn't quite solve this problem:
>
>> deparse(formula(myglm))
> [1] "y ~ x"
>> deparse(formula(myglm)[2])
> [1] "y()"
>> deparse(formula(myglm)[3])
> [1] "x()"
>
> Ideally the elegant method would, in this example, return the character
> strings "x", "y", and "DAT".
>
> Thanks for any insights.
>
> Jake
>
> Jacob A. Wegelin
> Assistant Professor
> Department of Biostatistics
> Virginia Commonwealth University
> 730 East Broad Street Room 3006
> P. O. Box 980032
> Richmond VA 23298-0032
> U.S.A.
> E-mail: jwegelin at vcu.edu
> URL: http://www.people.vcu.edu/~jwegelin
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at 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.
>