how many CRANextra mirror in the world?
r
Solution
The stated reason for offering a bounty is "Looking for an answer drawing from credible and/or official sources."
I would have thought that @JoshuaUlrich is a credible source, but since you're still looking for an answer, I would like to point you to http://stat.ethz.ch/CRAN/doc/FAQ/R-FAQ.html#Add_002don-packages-from-CRAN
At the end of that section of the R-FAQ, there is this paragraph:
Some CRAN packages that do not build out of the box on Windows, require additional software, or are shipping third party libraries for Windows cannot be made available on CRAN in form of a Windows binary packages. Nevertheless, some of these packages are available at the "CRAN extras" repository at http://www.stats.ox.ac.uk/pub/RWin/ kindly provided by Brian D. Ripley. Note that this repository is a default repository for recent versions of R for Windows.
While it doesn't explicitly state that this is the only "CRAN extras" repository, as it receives special mention on the official help page for the Comprehensive R Archive Network, in the section that describes the add-on packages from CRAN, I think this can be treated as an official source justifying Joshua's comment.
Problem
I have see a setup in someones .Rprofile ``` options(repos = c(CRAN = "http://streaming.stat.iastate.edu/CRAN", CRANextra = "http://www.stats.ox.ac.uk/pub/RWin")) ``` How many CRANextra mirror in the world? is there only one CRANextra mirror in the world?