R help - Jul 2009 - obtain names of variables and data from glm object

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@vcu.edu
URL: http://www.people.vcu.edu/~jwegelin

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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]]
>
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