Question

How can I set a specific CRAN mirror permanently in R?

I want to set it permanently in my laptop so that when I do install.packages(), it won’t ask me again which mirror to choose.

Answer 1

You can set repos in your .Rprofile to restore your choice every time you start R

Edit: to be more precise:

Add

options(repos=c(CRAN="THE URL OF YOUR FAVORITE MIRROR"))

to your .Rprofile, located in the home directory of your user.

You can find a list of CRAN mirrors here.

Example:

# add this line to ~/.Rprofile, restart your R session so it takes effect
options(repos=c(CRAN="http://cran.r-project.org"))

---

Alternatively, you can set the mirror site-wide in your Rprofile.site. The location of the file is given by ?Startup:

The
path of this file is taken from the value of the R_PROFILE
environment variable (after tilde expansion). If this variable is
unset, the default is R_HOME/etc/Rprofile.site, which is used if
it exists (which it does not in a ‘factory-fresh’ installation).

So do Sys.getenv("R_PROFILE") for the first option, or Sys.getenv("R_HOME") or R.home() for the second option. On macOS, the location of the second is /Library/Frameworks/R.framework/Resources/etc/.

The file may not exist, or you may see the following lines commented out :

# set a CRAN mirror
# local({r <- getOption("repos")
#       r["CRAN"] <- "http://my.local.cran"
#       options(repos=r)})

So remove the comment marks and change "http://my.local.cran" to the correct website, e.g.:

local({r <- getOption("repos")
       r["CRAN"] <- "http://cran.r-project.org"
       options(repos=r)})