R Resources

Software Installation

In order to work with R you will need to complete two following tasks:

• Install R itself on your machine.
• Get an editor to write your code.

The editor can independent of R, and can be usually used to write code in other languages. You can even use a basic text editor to write an R script, but this of course is sub-optimal.

The two option frequently used by R programmers are RStudio IDE and Emacs (for intermediate/advanced users).

You are free to pick an editor that you feel most comfortable with. However, all instructions and lecture materials will use Rstudio.

Installing R

• Visit the official R website. Click on “download R” or go to “CRAN” tab.
• The download link actually takes you to a list of mirror sites. Choose a site that is geographically close to you (USA, UC Berkeley).
• Choose your operating system (Linux/Mac OS/Windows)
• Download a binary file and follow the installation instructions for your system.

Installing RStudio

Install the latest version of RStudio. RStudio includes many cool features including interactive R Notebooks, and an integrated terminal window.

• Visit the following RStudio link
• Pick and download installer for your OS.
• After download is completed you can double-click the file and follow instructions to install the program.

Running R

The interpreter mode

To start the R console you can either

• launch the R graphical user interface.
• or type “R” from the command line/terminal.

To open a terminal window use:

• For linux: Ctr + Alt + T.
• For Mac: Command + space. Then, start typing “Terminal” and press Enter.
• For Windows: WinKey + R. Then, type “cmd” and press Enter.

Then, you can interactively give instructions to the computer, using the R commands. To quit enter q().

The R console is also available as one of the panes in the RStudio IDE, and is automatically started when you launch RStudio.

The scripting mode

• A more convenient way to interact with R is to write a script.
• A script contains all code you want to execute.
• You should write your R code in the editor.
• After you finish writing your R script, e.g. script.R, you can run the program:
  • from the terminal, browse to the location where you saved your script
  • then call Rscript script.R

R markdown / R Notebook

• In RStudio you can start a new document of type R Notebook/ R Markdown that let’s you combine text, code and the output of your code in the same report.
• The code in these documents is organized in chunks which can be evaluated inline, i.e. their output will be included right beneath the code. The R Markdown requires you to compile the entire document, whereas R Notebooks allow you to evaluate each chunks individually, not necessarily in order in which they appear.
• To start an R Notebook you should go to File > New File > R Notebook.
• To insert a new code chunk you should use a keyboard shortcut Ctrl + Alt + I (Mac OS X: Cmd + Option + I)
• To execute the code in a specific chunk: place your cursor inside that chunk then use the Run Chunk button or press Ctrl + Shift + Enter (Mac OS X: Cmd + Shift + Enter)

You can find more on R Notebooks here.

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Based on the R-bootcamp class by Lan Huong Nguyen (Stanford), edited by Claire Donnat.