[R] How to reinstall rpart?

[David Parkhurst]

After entering “library(rpart)”, I tried to plot an existing rpart tree, and
got this error message:  Error: couldn't find function "plot.rpart".
However, “?plot.rpart” does bring up the help for the function.  The same
things occur for text.rpart, although print(my.tree) does work.

So, I tried to re-install rpart using Packages  | Install from CRAN, but
then I get this message:––––––––––––––––––––––––––––––––––––––––––––––––––-

> local({a <- CRAN.packages()

+ install.packages(select.list(a[,1],,TRUE), .libPaths()[1], available=a)})

trying URL `http://cran.r-project.org/bin/windows/contrib/1.7/PACKAGES'

Content type `text/plain; charset=iso-8859-1' length 12560 bytes

opened URL

downloaded 12Kb



trying URL
`http://cran.r-project.org/bin/windows/contrib/1.7/rpart_3.1-12.zip'

Content type `application/zip' length 231827 bytes

opened URL

downloaded 226Kb



Error in unpackPkg(foundpkgs[okp, 2], pkgnames[okp], lib, installWithVers) :

        Can not remove prior installation of package

––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Evidently I need to uninstall first, but I can’t figure out how.  I’ve
looked in the pdf manuals, in the R FAQ, and in the R for Windows FAQ, and
don’t find instructions for doing so.  I’d appreciate any help.  Thanks.

Dave Parkhurst