R Help

R

R is a freeware statistical analysis program. First released as a "toy" package in 1995, it has become a leading stat package because of the improvements which are continually being contributed by statisticians world-wide. For home use, download it from Main R Site. For a tutorial, start R, (just type "R" on our Sun machines, or click the R icon in Windows) then type "help.start()" (or use the Help menu in Windows) and when the browser window opens, choose "Introduction to R". The sample session is a good place to start if you're in a hurry to see what R can do.
For up-to-date information and documentation, see the Main R Site.
You might also like R Programming WikiBook.

The original authors (Ross Ihaka and Robert Gentlemen) wanted to create an S-like language with the ability to handle loops and memory better than S or Splus. It started as a primitive language in 1996, and has grown exponentially since it it became an international project in 1997. Locally, it runs on our Sun workstations, just type R in a terminal window.

The reference manual for R is easily accessed with the help.start() command. R has some functions not available in SPLUS, for instance, dataentry() command opens a spreadsheet for data input. A few functions use different arguments, but most code works in either flavor of S.

Distribution and resources:

To get your own copy of R, documentation, and/or addons, or to find out about mailing lists, visit the Main R Site. Note the documentation links on the bottom left. We now have The R Journal.

Packages

R stores the current session (objects like data and functions) in memory. To keep memory usage small, it relies on packages which are objects which can be loaded when needed. The base package is always loaded, but other packages are only loaded when called, for example\ library(lattice) loads up a library of fancy plotting routines.

If you have a web connection and R for windows, packages can be downloaded with a few clicks under the packages menu, and you can easily update any or all of the packages you have installed. The windows distribution comes with 8 packages, but there are almost 2000 packages available (well, not all have a windows version).

R within Emacs on UNIX machines

On the unix machines, I strongly recommend running R from within the Emacs editor using ESS: Emacs Speaks Statistics, because it allows you to quickly revise and resubmit code. I use two windows running under one emacs session:

one window for the R session Start emacs as in:
```
> emacs &
```
Start R by typing Meta^X R (Meta^X means hold down the diamond key while you press x, then shift-R).
When it asks which directory to start in just return to run in the current directory or you can specify any subdirectory.
another containing the code I want to run and the output I want to save. Click on these options to open a new window:
```
File (Menu)
   New Frame
```
In the new window,
```
File (Menu)
   Open File
```
and type in a file name. It does not need to already exist. If the above commands don't work, you need to copy a specially tailored .emacs file to your root directory. One way to get one that works is to copy mine with the command:
```
gauss> cp ~jimrc/.emacs .emacs
```
(close and restart emacs if it's already going).

Help:
Within R, type:
```
 help.start()
```
and choose the introduction or the FAQ. The intro includes a sample session which you should work through.
You can get help on any function by typing help(function.name). However, it's hard to know what function toask for when just starting. For a partial list of useful functions see this reference card.
The command help.search("topic") searches the installed packages, and RSiteSearch("topic") searches the CRAN web site for functions related to some topic.
Quitting:
To exit R, type q() . It will ask if you want to save your session. If you type "y" (without the quotes), then the variables you've created in one session will be available for the next session. If you reply "n", then your recent data will be dumped. My advice is to keep all code so that you can re-run any analysis later. Then you do not need to save the session image.
If you have some functions which you use often, then you might want to clean up the workspace, input the functions, and save the image like this:
```
> objects()                     ## lists the data & functions in memory
> rm(temp1, olddata, etc)       ## remove old stuff
> source("file_of_functions.R") ## read in the functions
> save.image()          ## save the stuff in memory for future sessions
```
Info on unix and emacs.

Other Stat package demos for unix packages:
Back to MSU Math Department Home Page

Author: Jim Robison-Cox
Last Updated: Tuesday, 14-Jun-2011 16:52:23 MDT

R

Distribution and resources:

Packages

R within Emacs on UNIX machines

Help:

Quitting: