Re: [R] *not* using attach() *but* in one case ....

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Thu, 19 May 2011 11:26:23 +0100 (BST)

Hmm, load() does have an 'envir' argument. So you could simply use that and with() (which is pretty much what attach() does internally).

If people really wanted a lazy approach, with() could be extended to allow file names (as attach does).

On Thu, 19 May 2011, Martin Maechler wrote:

> [modified 'Subject' on purpose;
> Good mail readers will still thread correctly, using the 'References'
> and 'In-Reply-To' headers, however, unfortunately,
> in my limited experience, good mail readers seem to disappear more and more ..
> ]
>
>>>>>> Peter Ehlers <ehlers_at_ucalgary.ca>
>>>>>> on Tue, 17 May 2011 06:08:30 -0700 writes:
>
> > On 2011-05-17 02:22, Timothy Bates wrote:
> >> Dear Bryony: the suggestion was not to change the name of
> >> the data object, but to explicitly tell glm.nb what
> >> dataset it should look in to find the variables you
> >> mention in the formula.
> >>
> >> so the salient difference is:
> >>
> >> m1<- glm.nb(Cells ~ Cryogel*Day, data = side)
> >>
> >> instead of
> >>
> >> attach(side) m1<- glm.nb(Cells ~ Cryogel*Day)
> >>
> >> This works for other functions also, but not uniformly as
> >> yet (how I wish it did and I could say hist(x, data=side)
> >> Instead of hist(side$x)
> >>
> >> this inconsistency encourages the need for attach()
>
> > Only if the user hasn't yet been introduced to the with()
> > function, which is linked to on the ?attach page.
>
> > Note also this sentence from the ?attach page:
> > ".... attach can lead to confusion."
>
> > I can't remember the last time I needed attach().
> > Peter Ehlers
>
> Well, then you don't know *THE ONE* case where modern users of
> R should use attach() ... as I have been teaching for a while,
> but seem not have got enought students listening ;-) ...
>
> --- Use it instead of load() {for save()d R objects} ---
>
> The advantage of attach() over load() there is that loaded
> objects (and there maye be a bunch!), are put into a separate
> place in the search path and will not accidentally overwrite
> objects in the global "workspace".
>
> Of course, there are still quite a few situations {e.g. in
> typical BATCH use of R for simulations, or Sweaving, etc} where
> load() is good enough, and the extras of using attach() are not
> worth it.
>
> But the unconditional "do not use attach()"
> is not quite ok,
> at least not when you talk to non-beginners.
>
> Martin Maechler, ETH Zurich

-- 
Brian D. Ripley,                  ripley_at_stats.ox.ac.uk
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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Received on Thu 19 May 2011 - 10:33:02 GMT

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