On 24.02.2012 16:55, Joris Meys wrote:
Maybe I should rephrase:
As mentioned by Martin, by you and by TFM (which I read),
unloadNamespaces does not remove registered S3 methods. I got the
message before. As to why it has to be this way, the people that WTFM
didn't really add much information to TFM for those who RTFM (nor do
they have to). I merely wondered why it had to be that way out of
interest, but maybe formulated my question in a less clear and more
offensive way.
So:
Given the fact that S3 methods are not removed by unloading a namespace:
- What is the reason for this, as I would naively assume removing
them when unloading a namespace seems more useful?
Because there are no mechanisms implemented that keep the old
information, i.e. before things got registered.
- How do you remove them without having to restart R?
That is not possible.
Uwe Ligges
Sincerely,
Joris
2012/2/24 Prof Brian Ripley<rip...@stats.ox.ac.uk>:
fortunes::fortune('WTFM') applies. As already pointed out, ?detach says
If a package has a namespace, detaching it does not by default
unload the namespace (and may not even with ‘unload=TRUE’), and
detaching will not in general unload any dynamically loaded
compiled code (DLLs). Further, registered S3 methods from the
namespace will not be removed. If you use ‘library’ on a package
whose namespace is loaded, it attaches the exports of the already
loaded namespace. So detaching and re-attaching a package may not
refresh some or all components of the package, and is inadvisable.
And that is explicitly mentioned on ?unloadNamespace ....
On Fri, 24 Feb 2012, Joris Meys wrote:
2012/2/24 Prof Brian Ripley<rip...@stats.ox.ac.uk>:
As
getS3method('print', 'object_size')
would have confirmed the expectations of a 'one' with a less sketchy
understanding of R.
Yes, getS3method() sends you -not very surprisingly- to the one from
gdata. I realized, as print(object.size(iris)) gets that one as well,
and even in my sketchy understanding of R I suspect that both actions
have a similar underlying mechanism. But that's not my point.
Why would I have to expect the gdata version is still used (under the
correct assumption that I haven't been writing on the R source code
myself)? As a maybe-not-so-smart basic user of R, I would expect that
detach() and eventually unloadNamespace() would revert the effect of
library() (and loadNamespace() ). Apparently they don't.
The only way to reverse the action of require(gdata) seems to be to
restart R. That's at least what my limited brain could understand from
the valuable information given by both you and Martin. Seemingly
having to restart an application to undo an action, even in the
presence of functions with names that make you believe they revert a
former action, might in general be conceived as rather unexpected by
somebody with the same sketchy understanding of R as me. I would be
delighted if you could explain to me which part of R I understand
wrongly to come to this silly observation.
Sincerely,
Joris
--
Joris Meys
Statistical consultant
Ghent University
Faculty of Bioscience Engineering
Department of Mathematical Modelling, Statistics and Bio-Informatics
tel : +32 9 264 59 87
joris.m...@ugent.be
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--
Brian D. Ripley, rip...@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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