[R] installing, removing, upgrading, and downgrading packages

Christopher W. Ryan cryan at binghamton.edu
Wed Jul 11 17:57:13 CEST 2007

I'm very new to R, trying to learn it.  I started with R 2.4, but I have
since upgraded to 2.5.0, on WindowsXP.  I understand that 2.5.1 is now

Last night in the course of things I loaded libraries "coin" and
"survival".  I received warning messages that they had been built under
version 2.5.1.  However, as far as I could tell, they worked OK.  But
this brought some questions to mind:

I found the remove.packages() command.  Is there a way to revert a
package back to a previous version without removing it?  If not, and I
remove one version, how do I specify downloading a particular (earlier)

Was that warning of any consequence?  Are there times when a package
will not work properly with an earlier version of R, and will this be
obvious to me when I try to use it?  Or in a more general sense, are
there foreseeable circumstances in which an older version of a package
would be necessary, rather than the newest one?

Should I keep my packages in a library folder outside of the R install
folder?  Right now, it appears that all the packages I download get
installed into a library subdirectory under my R250 directory.
Advantages and disadvantages of either method?

Christopher W. Ryan, MD
SUNY Upstate Medical University Clinical Campus at Binghamton
40 Arch Street, Johnson City, NY  13790
PGP public keys available at http://home.stny.rr.com/ryancw/

"If you want to build a ship, don't drum up the men to gather wood,
divide the work and give orders. Instead, teach them to yearn for the
vast and endless sea."  [Antoine de St. Exupery]

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