What documentation exists for R?

Chapter 7: R Miscellanea 85
from SAS, for example). These do not depend on the order of factors in the model. The
question of which set of sums of squares is the Right Thing provokes low-level holy wars on
R-help from time to time.
There is no need to be agitated about the particular sums of squares that R reports. You
can compute your favorite sums of squares quite easily. Any two models can be compared
with anova(model1, model2), and drop1(model1) will show the sums of squares resulting
from dropping single terms.
7.19 How do I produce PNG graphics in batch mode?
Under Unix, the png() device uses the X11 driver, which is a problem in batch mode or
for remote operation. If you have Ghostscript you can use bitmap(), which produces a
PostScript file then converts it to any bitmap format supported by Ghostscript. On some
installations this produces ugly output, on others it is perfectly satisfactory. In theory one
could also use Xvfb from X.Org, which is an X11 server that does not require a screen; and
the GDD package from CRAN, which produces PNG, JPEG and GIF bitmaps without X11.
7.20 How can I get command line editing to work?
The Unix command-line interface to R can only provide the inbuilt command line editor
which allows recall, editing and re-submission of prior commands provided that the GNU
readline library is available at the time R is configured for compilation. Note that the
‘development’ version of readline including the appropriate headers is needed: users of
Linux binary distributions will need to install packages such as libreadline-dev (Debian)
or readline-devel (Red Hat).
7.21 How can I turn a string into a variable?
If you have
you can do
for
or
for
or
for
varname