[r] Installing R with Homebrew

I'm trying to install R using Homebrew. I ran these commands which are recommended elsewhere on SO:

brew tap homebrew/science
brew install R

For brew tap homebrew/science, I'm receiving this error:

Error: Already tapped!

For the second command, I receive this:

Error: No available formula for r 

Any suggestions?

As of 2017 / Brew 1.3.2 @ macOS Sierra 10.12.6 all you have to do is:

$ brew install r

You don't even need to tap homebrew/science since r is now a part of core formulae for the Homebrew (homebrew-core).

It will also install all dependencies automatically:

==> Installing dependencies for r: gmp, mpfr, libmpc, isl, gcc

There are two additional options you might want to know:

--with-java
Build with java support
--with-openblas
Build with openblas support

brew install cask
brew cask install xquartz
brew tap homebrew/science
brew install r

This way, everything is packager managed, so there's no need to manually download and install anything.

If you run

xcode-select --install

you do you not need to install gcc through brew, and you will not have to waste time compiling gcc. See https://stackoverflow.com/a/24967219/2668545 for more details.

After that, you can simply do

brew tap homebrew/science
brew install Caskroom/cask/xquartz
brew install r

You can also install R from this page:

https://cran.r-project.org/bin/macosx/

It works out of the box

I am working MacOS 10.10. I have updated gcc to version 4.9 to make it work.

brew update
brew install gcc
brew reinstall r

If you meant "r" specifically:
It was migrated from homebrew/science to homebrew/core.

For r 3.4.3 Mac High Sierra:

brew tap homebrew/core
brew install Caskroom/cask/xquartz
brew install r

This is what actually worked for me on OSX Yosemite.

brew install cask
brew install Caskroom/cask/xquartz
brew install r

brew install homebrew/science/r

works on OS X 10.11.6.

homebrew/science was deprecated So, you should use the following command.

brew tap brewsci/science

I used this tutorial to install R on my mac, and it had me install xquartz and a fortran complier (gfortran) as well.

My suggestion would be to brew untap homebrew/science and then brew tap homebrew/science and try again, also, make sure you don't have any errors when you run brew doctor

Hope this helps

Working on El Capitan 10.11.1, the steps I followed are

brew install cask    
brew tap homebrew/science    
brew install r