On Wed, 24 Mar 2004, Christian Hoffmann wrote:
> Hi all,
>
> I just cannot think of how to do it:
> I want to take the first variable (column) of a data frame and regress
> it against all other variables.
>
> bla <- function (dat) {
> reg <- lm(whateverthefirstofthevariablenamesis ~., data=dat)
> return(reg)
> }
>
> What kind of function do I have to take instead of the
> whateverthefirstofthevariablenamesis,
>
> eval(), substitute(), get(), ...
>
> to correctly compute this regression?
>
> With lm(get(names(dat)[1] ~., data=dat) there are no errors, but the
> first variable also shows up among the regressors.
Andy Liaw has pointed out that lm(dat) happens to work. But for a more
generalizable solution try
bla <- function (dat)
eval(substitute(lm(foo ~., data=dat), list(foo=as.name(names(dat)[1]))))
which has the advantage of embedding a clean value of $call.
--
Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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