U of Minnesota Statistics: R and Rweb

under construction This page still under construction. Don't look yet. Or you can look, but be warned it's unfinished.

Table of Contents

R

R is a general purpose computing language especially designed for statistics. For more info on R, see the R archive. There it says

R, also known as `GNU S', is a system for statistical computation and graphics. It consists of a language plus a run-time environment with graphics, a debugger, access to certain system functions, and the ability to run programs stored in script files. R implements a language which is not entirely unlike the S language developed at AT&T Bell Laboratories by Rick Becker, John Chambers and Allan Wilks. Indeed in the absence of an R manual, you can (mostly) get along by using the S manual.

The S computing language was invented by a group at Bell Labs (that's why its name is only one letter like C). It still is an active research project at Bell Labs. S is marketed by Insightful Corporation under the name S-PLUS. Although S-PLUS contains extra features added by Insightful (and its predecessor companies Mathsoft and Statistical Science Inc.), the core language comes from Bell Labs.

R is 80 to 90% compatible with S (S-PLUS). Some incompatibilities are deliberate design decisions (see the R FAQ under What are the differences between R and S?). Some are features of S (S-PLUS) that the R team have not yet implemented.

To run R on a UNIX computer in the School of Statistics, just say R at a UNIX prompt. To get out (as with S), say q() at an R prompt. To get the on-line help either do

   help.start()

at an R prompt. Or just go to to the URL

   http://rweb.stat.umn.edu/R/doc/html/

with any web browser.

Rweb

Rweb is an implementation of R that can be run over the web. For more info on Rweb see the Rweb home page.

Our local Rweb server is on a different web server from these pages

   http://rweb.stat.umn.edu/Rweb/

(note rweb.stat.umn.edu rather than www.stat.umn.edu). The documentation for the version of R used on the server is at the URL

   http://rweb.stat.umn.edu/R/doc/html/

and this should always be the same version of R as is on the department workstations.

To run Rweb, you type some statements in the R language into the "R commands" window below and click "submit". The commands will be executed and the results displayed on a new web page. When you've looked at that page all you want, click the "back" button on your browser to return here.

External Data Entry

Enter a dataset URL :

A simple bit of R is any arithmetic expression. You can use it as a calculator. If you type "2 + 2" in the "R Commands" window and click "submit", Rweb will reply

     Rweb:> 2 + 2 
     [1] 4

The "Dataset URL" window allows you to type in a URL that contains an R dataset. For example if you type

  http://www.stat.umn.edu/geyer/somedata

in the "Dataset URL" window and

  plot(x, y)
  out <- lm(x ~ y)
  summary(out)
  abline(out)

in the "R Commands" window, and click "submit", you get a scatter plot with regression line for the data in that dataset.


Questions or comments to: Charles Geyer charlie@stat.umn.edu