How do I reinstall a base-R package (e.g., stats, graphics, utils, etc.)?

Question

I have been using the \"stats\" package in R 3.0.1 without any problems . But today i deleted the \"stats\" folder from the R library location and now I can\'t install it an

Answer 1

What worked for me was to copy the entire package folder from another to my R.home() directory.

Answer 2

(Since SO is nagging me not to continue the comment thread, I will post an answer.)

I believe that this problem will apply to any base package (but not to those installed from repositories, and probably not to Recommended packages): I am deeply skeptical that stats is the only package. It should occur for any of the packages in this list:

rownames(subset(as.data.frame(installed.packages()),Priority=="base"))

I'm sure it's theoretically possible to re-install a base package from scratch, but it will be much easier to re-install R. At a guess, it would take me about 15 minutes to re-install R, and I would feel lucky if I figured out how to re-install a base package on its own in less than an hour.

I'm pretty sure that re-installing R will not affect previously-installed packages: see e.g. http://cran.r-project.org/bin/windows/base/rw-FAQ.html#How-do-I-UNinstall-R_003f; that link is about uninstalling rather than re-installing, but this seems relevant:

Uninstalling R only removes files from the initial installation, not (for example) packages you have installed or updated.

Other choices would be

• create another identical installation of R (on another machine, or in a non-default location); locate the relevant directories in your new installation and copy them over to your existing installation.
• restore the relevant directories from your backup.

PS: obviously if you are doing this on a client's machine it would be a good idea to test my advice first ...