| options {base} | R Documentation |
Allow the user to set and examine a variety of global “options” which affect the way in which R computes and displays its results.
options(...) getOption(x) .Options
... |
any options can be defined, using name = value or
by passing a list of such tagged values. However, only the ones
below are used in “base R”.
Further, options('name') == options()['name'], see the example.
|
x |
a character string holding an option name. |
Invoking options() with no arguments returns a list with the
current values of the options. Note that not all options listed below
are set initially. To access the value of a single option, one should
use getOption("width"), e.g., rather than
options("width") which is a list of length one.
.Options also always contains the options() list (as a
pairlist) , for S compatibility. You must use it “read only”
however.
For options, a list (in any case) with the previous values of
the options changed, or all options when no arguments were given.
prompt:" ").continue:width:digits:print.default.editor:edit. Set from the environment variable
VISUAL on UNIX.pager:file.show and
sometimes help.
Defaults to ‘$R_HOME/bin/pager’.
browser:help.start() on UNIX, or a non-default browser on
Windows.pdfviewer:R_PDFVIEWER.mailer:bug.report(). Can be "none".contrasts:contrasts used in
model fitting such as with aov or lm.
A character vector of length two, the first giving the function to
be used with unordered factors and the second the function to be
used with ordered factors.defaultPackages:R_DefaultPackages, or if that is unset
to c("utils", "stats", "graphics", "methods"). (Set
R_DEFAULT_PACKAGES to NULL or a comma-separated list
of package names.) A call to options should be in your
‘.Rprofile’ file to ensure that the change takes effect
before the base package is initialized (see Startup).expressions:keep.source:TRUE, the source code for
functions (newly defined or loaded) is stored in their
"source" attribute (see attr) allowing
comments to be kept in the right places.
The default is interactive(), i.e., TRUE for
interactive use.
keep.source.pkgs:keep.source, for
functions in packages loaded by library or
require. Defaults to FALSE unless the
environment variable R_KEEP_PKG_SOURCE is set to
yes.na.action:NA's) for certain situations.papersize:postscript; set by environment variable
R_PAPERSIZE when R is started and defaulting to
"a4" if that is unset or invalid.printcmd:postscript
for printing; set by environment variable R_PRINTCMD when
R is started. This should be a command that expects either input
to be piped to ‘stdin’ or to be given a single filename
argument.
latexcmd, dvipscmd:show.signif.stars, show.coef.Pvalues:printCoefmat.ts.eps:ts) computations.error:stop as well as by signals and internally detected
errors. If the option is a function, a call to that function,
with no arguments, is generated as the expression. The default
value is NULL: see stop for the behaviour in
that case. The function dump.frames provides one
alternative that allows post-mortem debugging.show.error.messages:try or a
user-installed error handler.warn:warn is negative all warnings are ignored. If warn
is zero (the default) warnings are stored until the top–level
function returns. If fewer than 10 warnings were signalled they
will be printed otherwise a message saying how many (max 50) were
signalled. A top–level variable called last.warning is
created and can be viewed through the function
warnings. If warn is one, warnings are
printed as they occur. If warn is two or larger all
warnings are turned into errors.warning.length:warning.expression:warn.check.bounds:FALSE. If
true, a warning is produced whenever a “generalized
vector” (atomic or list) is extended, by something
like x <- 1:3; x[5] <- 6.echo:FALSE.verbose:TRUE by the command-line option
--verbose.device:x11, windows or gtk) for an
interactive session, and postscript in batch use or if a
screen is not available.X11colortype:X11 devices.CRAN:update.packages. Defaults to
http://cran.r-project.org.repositories:pkgDepends. The default
return value for the function is a vector with two components, one the
value of contrib.url(getOption("CRAN")) and the second
contrib.url(getOption("BIOC")).download.file.method:download.file. Currently download methods
"internal", "wget" and "lynx" are available.
There is no default for this option, when method = "auto"
is chosen: see download.file.unzip:R_UNZIPCMD, which is set in
‘etc/Renviron’ if an unzip command was found during
configuration.de.cellwidth:dataentry.
If this is unset, 0, negative or NA, variable cell widths
are used.encoding:native.enc (= 0:255).
See connections.timeout:download.file and connections.internet.info:scipen:scipen digits wider.locatorBell:locator
and identify be confirmed by a bell. Default TRUE.
Honoured at least on X11 and windows devices.X11fonts:X11.The default settings of some of these options are
prompt | "> " | continue | "+ " |
width | 80 | digits | 7 |
expressions | 500 | keep.source | TRUE |
show.signif.stars | TRUE | show.coef.Pvalues | TRUE |
na.action | na.omit | ts.eps | 1e-5 |
error | NULL | show.error.messages | TRUE |
warn | 0 | warning.length | 1000 |
echo | TRUE | verbose | FALSE |
scipen | 0 | locatorBell | TRUE |
Others are set from environment variables or are platform-dependent.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
options() # printing all current options
op <- options(); str(op) # nicer printing
# .Options is the same:
all(sapply(1:length(op), function(i) if(is.atomic(op[[i]]))
{all(.Options[[i]] == op[[i]])} else TRUE))
options('width')[[1]] == options()$width # the latter needs more memory
options(digits=20)
pi
# set the editor, and save previous value
old.o <- options(editor="nedit")
old.o
options(check.bounds = TRUE)
x <- NULL; x[4] <- "yes" # gives a warning
options(digits=5)
print(1e5)
options(scipen=3); print(1e5)
options(op) # reset (all) initial options
options('digits')
## Not run:
## set contrast handling to be like S
options(contrasts=c("contr.helmert", "contr.poly"))
## End(Not run)
## Not run:
## on error, terminate the R session with error status 66
options(error=quote(q("no", status=66, runLast=FALSE)))
stop("test it")
## End(Not run)
## Not run:
## set an error action for debugging: see ?debugger.
options(error=dump.frames)
## A possible setting for non-interactive sessions
options(error=quote({dump.frames(to.file=TRUE); q()}))
## End(Not run)