R devel - Apr 2007 - how to control which version of a package library() installs?

library() seems to remember the location of a package when I give it a 
lib.loc, and then use that version thereafter, even if I don't supply 
lib.loc again.  Is there any way I can load different versions of a 
package in one R session? -- I don't seem to able to simply detach the 
package and then load a different version from a different library location.

$ R
[...startup info...]
 > # only version we currently know about is in the standard library
 > .find.package("ExamplePackage")
[1] "c:/R/R-2.4.1/library/ExamplePackage"
 > # load a version from a different library e:/devinst
 > library(ExamplePackage, lib.loc="e:/devinst")
 > # and check we've got the right version ... yes
 > system.file(package="ExamplePackage")
[1] "e:/devinst/ExamplePackage"
 > .find.package("ExamplePackage")
[1] "e:/devinst/ExamplePackage"
 > detach(2)
 >
 > # Now I'd like to load the version in the standard library.
 > # .find.package() finds the version I want
 > .find.package("ExamplePackage")
[1] "c:/R/R-2.4.1/library/ExamplePackage"
 > # but library() loads the same version it did before, even
 > # though I don't supply lib.loc, and .libPaths is untouched.
 > library(ExamplePackage)
 > system.file(package="ExamplePackage")
[1] "e:/devinst/ExamplePackage"
 > .find.package("ExamplePackage")
[1] "e:/devinst/ExamplePackage"
 > .libPaths()
[1] "c:/R/R-2.4.1/library"
 > sessionInfo()
R version 2.4.1 (2006-12-18)
i386-pc-mingw32

locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United 
States.1252;LC_MON
ETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United 
States.1252


attached base packages:
[1] "stats"     "graphics"  "grDevices"
"utils"     "datasets"  "methods"
[7] "base"

other attached packages:
ExamplePackage
          "1.0"
 >

Am I doing something wrong here?  I can't find any mention of 
persistence of package location in ?library.

thanks for any help or suggestions,

Tony Plate

On Fri, 13 Apr 2007, Tony Plate wrote:
> library() seems to remember the location of a package when I give it a
> lib.loc, and then use that version thereafter, even if I don't supply
Not quite: it notices that it is loaded and does not load it again, 
possibly attaching the exports of a still-loaded namespace.
> lib.loc again.  Is there any way I can load different versions of a
> package in one R session? -- I don't seem to able to simply detach the
> package and then load a different version from a different library
location.
Without the output of search(), searchpath() and loadedNamespace() we 
cannot know what happened here.  But here is an example of my own
> library(Matrix, lib.loc="~/R/test26")
Loading required package: lattice
> searchpaths()
  [1] ".GlobalEnv"
  [2] "/data/gannet/ripley/R/test26/Matrix"
  ...
> detach(2)
> search()
  [1] ".GlobalEnv"        "package:lattice"  
"package:stats"
  [4] "package:graphics"  "package:grDevices"
"package:utils"
  [7] "package:datasets"  "package:methods"  
"Autoloads"
[10] "package:base"
> library(Matrix, lib.loc="~/R/test-library")
> searchpaths()
  [1] ".GlobalEnv"
  [2] "/data/gannet/ripley/R/test26/Matrix"
  ...

The point is that the namespace Matrix is still loaded.
> detach(2)
> unloadNamespace("Matrix")
> library(Matrix, lib.loc="~/R/test-library")
> searchpaths()
  [1] ".GlobalEnv"
  [2] "/data/gannet/ripley/R/test-library/Matrix"

Might your example be similar?

> $ R
> [...startup info...]
> > # only version we currently know about is in the standard library
> > .find.package("ExamplePackage")
> [1] "c:/R/R-2.4.1/library/ExamplePackage"
> > # load a version from a different library e:/devinst
> > library(ExamplePackage, lib.loc="e:/devinst")
> > # and check we've got the right version ... yes
> > system.file(package="ExamplePackage")
> [1] "e:/devinst/ExamplePackage"
> > .find.package("ExamplePackage")
> [1] "e:/devinst/ExamplePackage"
> > detach(2)
> >
> > # Now I'd like to load the version in the standard library.
> > # .find.package() finds the version I want
> > .find.package("ExamplePackage")
> [1] "c:/R/R-2.4.1/library/ExamplePackage"
> > # but library() loads the same version it did before, even
> > # though I don't supply lib.loc, and .libPaths is untouched.
> > library(ExamplePackage)
> > system.file(package="ExamplePackage")
> [1] "e:/devinst/ExamplePackage"
> > .find.package("ExamplePackage")
> [1] "e:/devinst/ExamplePackage"
> > .libPaths()
> [1] "c:/R/R-2.4.1/library"
> > sessionInfo()
> R version 2.4.1 (2006-12-18)
> i386-pc-mingw32
>
> locale:
> LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
> States.1252;LC_MON
> ETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United
> States.1252
>
>
> attached base packages:
> [1] "stats"     "graphics"  "grDevices"
"utils"     "datasets"  "methods"
> [7] "base"
>
> other attached packages:
> ExamplePackage
>          "1.0"
> >
>
> Am I doing something wrong here?  I can't find any mention of
> persistence of package location in ?library.
>
> thanks for any help or suggestions,
>
> Tony Plate
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
-- 
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