R help - Jan 2011 - Passing formula as an agrument

Hi,

I had a function that looked like:

diff <- lm(x ~ y + z)

How can I pass the argument to the 'lm' function on the fly? E.g., if I
pass it
in as a string (e.g. "x ~ y + z"), then the lm function treats it as a
string
and not a proper argument.

many thanks


      
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Hi Tim,

I already answered this exact question from a different poster (by the
name of Paul Evans, subject: "Passing in arguments into function"),
that occurred within marvelous temporal proximity to your own, so I
will just refer you to that (search the archives with name + subject).

Just as a note, diff() is a function, so it is probably best to give
the variable you store the results of a call to lm() in a different
name, even if it is trivially different:

diff1 <- lm(x ~ y + z)

It can help to prevent future confusion and headache.

Cheers,

Josh

On Sun, Jan 23, 2011 at 8:44 AM, Tim Smith <tim_smith_666 at yahoo.com>
wrote:
> Hi,
>
> I had a function that looked like:
>
> diff <- lm(x ~ y + z)
>
> How can I pass the argument to the 'lm' function on the fly? E.g.,
if I pass it
> in as a string (e.g. "x ~ y + z"), then the lm function treats it
as a string
> and not a proper argument.
>
> many thanks
>
>
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/