[R] proper work-flow with 'formula' objects and lm()

[Gabor Grothendieck]

On Thu, Nov 24, 2011 at 2:48 PM, Liviu Andronic <landronimirc at gmail.com> wrote:
> Dear all
> I have a work-flow issue with lm(). When I use
>> lm(y1~x1, anscombe)
>
> Call:
> lm(formula = y1 ~ x1, data = anscombe)
>
> Coefficients:
> (Intercept)           x1
>     3.0001       0.5001
>
>
> I get as expected the formula, "y1 ~ x1", in the print()ed results or
> summary(). However, if I pass through a formula object
>> (form <- formula(y1~x1))
> y1 ~ x1
>> lm(form, anscombe)
>
> Call:
> lm(formula = form, data = anscombe)
>
> Coefficients:
> (Intercept)           x1
>     3.0001       0.5001
>
>
> then I only get the object name in the call, 'form', instead of the
> formula. When passing a 'formula' object to lm, is it possible to
> retain in the resulting 'lm' object the actual formula used for the
> regression: "y1 ~ x1"?
>

Try this:

> form <- formula(y1~x1)
> do.call("lm", list(form, quote(anscombe)))

Call:
lm(formula = y1 ~ x1, data = anscombe)

Coefficients:
(Intercept)           x1
     3.0001       0.5001

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