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THE BASIC R README (See "RESOURCES" for additional resources) 1. INTRODUCTION This directory contains the Unix source code tree for R, which is 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 (present) absence of an R manual, you can (mostly) get along by using the S manual. R is free software distributed under a GNU-style copyleft. Currently the software is undergoing active development. Discussion of the development process is carried out on the "r-devel" mailing list. See the file RESOURCES for details on how to subscribe to this list. 2. HISTORY R was initially written by Robert Gentleman and Ross Ihaka of the Statistics Department of the University of Auckland. In addition, a large group of individuals has contibuted to R by contributing code and bug reports. Since mid-1997 there has been a core group who can modify the R source code CVS archive. The group currently consists of Peter Dalgaard, Robert Gentleman, Kurt Hornik Ross Ihaka, Friedrich Leisch, Thomas Lumley, Martin Maechler, Paul Murrell, Heiner Schwarte and Luke Tierney. As noted above, discussions of the development process take place in the r-devel mailing list. 3. PRESENT STATUS The present version implements most of the functionality in the first S book (the "Blue Book") and many of the applications. In addition, we have implemented a certain amount of functionality from the second S book (the "White Book"). In particular we have a functioning versions of "lm" and "glm" and their associated "summary" and "anova" methods (it would be nice to have "drop1", "add1" and "step", but there hasn't been time to complete these yet). Some of us would like to see contributions for building "gam". What we have in the way of manual is in the directory in an "output independent" form which can be used to create versions for HTML, LaTeX, troff etc. 4. GOALS Our aim at the start of this project was to demonstrate that it was possible to produce an S-like environment which did not suffer from the memory-demands and performance problems which S has. It is only recently that we have started trying to turn R into a "real" system. In the short term we hope to create a small portable free system which will provide most of the functionality of S and perhaps some extensions. Future versions will see R converted to GNU coding standards. 5. SOME DIFFERENCES BETWEEN R AND S 1. In R, "factor" and "ordered factor" are primitive vector types. This means in particular that they can be shaped as arrays. 2. In R a list is a Lisp-style list composed of dotted pairs, rather than a vector of generic elements as in S. This means that list subscripting can be rather inefficient. However, lists are rarely large and so we have not (yet) bothered to implement a matching "generic vector" type, even though this could be quite useful. Robert Gentleman + Ross Ihaka + The R core.