On Fri, 24 Feb 2012, Joris Meys wrote:
Indeed, when trying :
detach('package:gdata',unload=TRUE)
print(object.size(iris),units='Kb')
[1] 6424
However, when I do :
unloadNamespace('gdata')
gc()
used (Mb) gc trigger (Mb) max used (Mb)
Ncells 380471 10.2 667722 17.9 597831 16.0
Vcells 353363 2.7 905753 7.0 902804 6.9
The function used is still print.object_size from gdata
print(object.size(iris),units='Kb')
[1] 6424
But it can't be found any more...
getAnywhere('print.object_size')
A single object matching ‘print.object_size’ was found
It was found in the following places
registered S3 method for print from namespace utils
namespace:utils
with value
... (here is indeed the code of the original print.object_size)
As
getS3method('print', 'object_size')
would have confirmed the expectations of a 'one' with a less sketchy
understanding of R.
This is not some kind of behaviour one would expect. I have no clue
how to solve this, but I believe it's safe to say that there's room
for improvement somewhere to avoid calling a function that's
apparently not in the search space. Any other ideas?
R relies very heavily on 'calling a function that's apparently not in
the search space': that's much of the point of namespaces.
Professor Ripley
Cheers
Joris
On Fri, Feb 24, 2012 at 1:08 PM, Prof Brian Ripley
<rip...@stats.ox.ac.uk> wrote:
On 24/02/2012 11:20, Martin Maechler wrote:
Joris Meys<jorism...@gmail.com>
on Fri, 24 Feb 2012 11:24:35 +0100 writes:
> I ran into some very irritating behaviour I don't
> understand. Let me illustrate with the package gdata()
> and the function print.object_size() :
>> print(object.size(iris),units='Kb')
> 6.3 Kb
>> getAnywhere(print.object_size)
> A single object matching ‘print.object_size’ was found It
> was found in the following places registered S3 method for
> print from namespace utils namespace:utils with value ...
> All is well. So now I load gdata
>> require(gdata)
> Loading required package: gdata ... The following
> object(s) are masked from ‘package:utils’:
> object.size
> OK, this is what I would expect:
>> print(object.size(iris),units='Kb')
> [1] 6424
>> getAnywhere(print.object_size)
> 2 differing objects matching ‘print.object_size’ were
> found in the following places registered S3 method for
> print from namespace utils namespace:gdata namespace:utils
> Use [] to view one of them
> Now I detach gdata again
>> detach(package:gdata)
> But the function print.object_size is still the default
> for object_size objects!
>> print(object.size(iris),units='Kb')
> [1] 6424
> And it can still be found as well:
>> getAnywhere(print.object_size)
> 2 differing objects matching ‘print.object_size’ were
> found in the following places registered S3 method for
> print from namespace utils namespace:gdata namespace:utils
> Use [] to view one of them
> Am I missing something?
Yes: the argument 'unload' of detach().
In general: Now that every package has a namespace,
you (and others) should learn the difference between
attaching and loading - and hence detach()ing and unloading
a package with its namespace.
?detach
?library
etc should give a good start.
A very good point, but actually there is more to this one. 'gdata'
registers an S3 method which overwrites the one from utils. Unloading a
namespace does not unregister its methods (and registration has no stack, so
there is no way R knows what was there before).
--
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
--
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
-------------------------------
Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php
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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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