[R-sig-teaching] pros/cons of teaching attach()

[Laura Chihara]

This thread is interesting. For those who use the
subset command, when you extract a variable from a
data frame, do you give it the same name as in the data set?

For instance,

my.data with variables trout, whale

trout <- subset(my.data, select=trout, drop=T)

I guess if you never attach, then you don't have to
worry about masking in the future.

Thanks

-Laura
On 9/21/2010 11:34 PM, Joshua Wiley wrote:
> Hi all,
>
> I am wondering if anyone teaches the attach function to new students
> and if so, why?
>
>
> I have never taught a class using R, but in small tutorials and
> providing direct help, I have run across this issue several times.  I
> have always avoided it, but a couple of times, students had learned to
> use it in a class (though without much detail) and were rather grumpy
> with me for using full variable names or with().  New converts,
> particularly from GUIs like SPSS, already tend to be leery of R, and I
> hate to make working at the command line more onerous since any typing
> is more than they are used to, but at the same time a discussion of
> environments, which I think is necessary to avoid trouble with attach,
> does not seem like beginner material either.
>
> I have wondered about this many times, but was just reminded again by
> an R-help post.
>
> Thanks,
>
> Josh
>

-- 
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Laura Chihara
Professor of Mathematics  507-222-4065 (office)
Dept of Mathematics       507-222-4312 (fax)
Carleton College
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