I recently took the plunge to upgrade R to 2.15.  As I was pondering the best way to install all my favorite packages, I stumbled upon this very helpful post from HLPlab

http://hlplab.wordpress.com/2012/06/01/transferring-installed-packages-between-different-installations-of-r/

The post describes a very handy way of ensuring that all your favorite packages make it to your new install.  Basically this is done via a handy set of code, and involves: 1) saving the names of your packages to a location, and then 2) calling R to then install those packages by name into your new version.

The code with descriptions can be found below:

1. Run the script “store_packages.R” in your current version of R.

# store_packages.R # # stores a list of your currently installed packages

tmp = installed.packages()

installedpackages = as.vector(tmp[is.na(tmp[,"Priority"]),

save(installedpackages, file=”~/Desktop/installed_packages.rda”)

Make sure that all the quotation marks in the script are straight.  The scripts will generate an error if they include any curly quotation marks.  For some reason, when I saved this blog entry, some quotation marks changed to curly ones.  WordPress is probably to blame for this problem, which I have not been able to fix.)

2. Close R.  Open the installation of R that you want the packages to be installed in.

3. Run the script “restore_packages.R”.

# restore_packages.R # # installs each package from the stored list of packages

load(“~/Desktop/installed_packages.rda”)

for (count in 1:length(installedpackages)) install.packages(installedpackages[count])

Note that if you want to install the list of packages in an installation of R on a different computer, you should transfer the .rda file that is created by the store_packages script to that computer, and make sure that the path for the “load” command in the restore_packages script is set to the right location.

However, for me, this all may change with my next upgrade–perhaps, as I chose the option to save my packages to a personal library (when 2.15 gave me the option) and my packages are now stored in a different location:

The downloaded binary packages are in
C:\Users\Chris\AppData\Local\Temp\RtmpiCX9N6\downloaded_packages