Update R using RStudio

How can I update R via RStudio?

For completeness, the answer is: you can't do that from within RStudio. @agstudy has it right - you need to install the newer version of R, then restart RStudio and it will automagically use the new version, as @Brandon noted.

It would be great if there was an update.R() function, analogous to the install.packages() function or the update.packages(function).

So, in order to install R,

1. go to http://www.r-project.org,
2. click on 'CRAN',
3. then choose the CRAN site that you like. I like Kansas: http://rweb.quant.ku.edu/cran/.
4. click on 'Download R for XXX' [where XXX is your operating system]
5. follow the installation procedure for your operating system
6. restart RStudio
7. rejoice

--wait - what about my beloved packages??--

ok, I use a Mac, so I can only provide accurate details for the Mac - perhaps someone else can provide the accurate paths for windows/linux; I believe the process will be the same.

To ensure that your packages work with your shiny new version of R, you need to:

1. move the packages from the old R installation into the new version; on Mac OSX, this means moving all folders from here:

   /Library/Frameworks/R.framework/Versions/2.15/Resources/library
   

   to here:

   /Library/Frameworks/R.framework/Versions/3.0/Resources/library
   

   [where you'll replace "2.15" and "3.0" with whatever versions you're upgrading from and to. And only copy whatever packages aren't already in the destination directory. i.e. don't overwrite your new 'base' package with your old one - if you did, don't worry, we'll fix it in the next step anyway. If those paths don't work for you, try using installed.packages() to find the proper pathnames.]

2. now you can update your packages by typing update.packages() in your RStudio console, and answering 'y' to all of the prompts.

   > update.packages(checkBuilt=TRUE)
   class :
    Version 7.3-7 installed in /Library/Frameworks/R.framework/Versions/3.0/Resources/library 
    Version 7.3-8 available at http://cran.rstudio.com
   Update (y/N/c)?  y
   ---etc---
   

3. finally, to reassure yourself that you have done everything, type these two commands in the RStudio console to see what you have got:

   > version
   > packageStatus()
   

You install a new version of R from the official website.

RStudio should automatically start with the new version when you relaunch it.

In case you need to do it manually, in RStudio, go to :Tools -> options -> General.

Check @micstr's answer for a more detailed walkthrough.

If you are using windows, you can use installr. Example usage here