options {base} | R Documentation |
options
allows 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 .
However, only the ones below are used in ``base R''. Further, options('name') == options()['name'] , see the example.
|
prompt |
a string, used for R's prompt; should usually end in a
blank (" " ). |
continue |
a string setting the prompt used for lines which continue over one line. |
width |
controls the number of characters on a line. You may want to change this if you re-size the window that R is running in. Valid values are 10...10000 with default normally 80. (The valid values are in file `Print.h' and can be changed by re-compiling R.) |
digits |
controls the number of digits to print when printing numeric values. It is a suggestion only. Valid values are 1...22 with default 7. |
editor |
sets the default text editor, e.g., for
edit . Set from the environment variable VISUAL
on UNIX. |
pager |
the (stand-alone) program used for displaying ASCII files on R's console. Defaults to `$R_HOME/bin/pager'. |
browser |
default HTML browser used by help.start()
on UNIX. |
mailer |
default mailer used by bug.report() . can
be "none" . |
contrasts |
the default 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. |
expressions |
sets a limit on the number of nested expressions that will be evaluated. This is especially important on the Macintosh since stack overflow is likely if this is set too high. Valid values are 25...100000 with default 500. |
keep.source |
When 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 |
As for 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 |
the name of a function for treating missing values
(NA 's) for certain situations. |
papersize |
the default paper format used by postscript ;
set by environment variable R_PAPERSIZE when R is started
and defaulting to "a4" if that is unset or invalid. |
printcmd |
the command used by 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 |
character strings giving commands to be used in off-line printing of help pages. |
show.signif.stars, show.coef.Pvalues |
logical, affecting P value
printing, see print.coefmat . |
ts.eps |
the relative tolerance for certain time series
(ts ) computations. |
error |
either a function or an expression governing the handling
of non-catastrophic errors such as those generated by
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 |
a logical. Should error messages be
printed? Intended for use with try or a
user-installed error handler. |
warn |
sets the handling of warning messages. If warn
is negative all warnings are ignored. If warn is zero
(the default) warnings are stored until the toplevel function
returns. If fewer than 10 warnings were signalled they will be printed
otherwise a message saying how many (max 50) were signalled. A
toplevel 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. |
check.bounds |
logical, defaulting to 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 |
logical. Only used in non-interactive mode, when it
controls whether input is echoed. Command-line options
--quiet and --slave set this initially to FALSE . |
verbose |
logical. Should R report extra information on
progress? Set to TRUE by the command-line option
--verbose . |
device |
a character string giving the default device for that
session. This defaults to the normal screen device (e.g. x11 ,
windows or gtk ) for an interactive session, and
postscript in batch use or if a screen is not available. |
X11colortype |
The default colour type for X11 devices. |
CRAN |
The URL of the preferred CRAN node for use by
update.packages . Defaults to
http://cran.r-project.org. |
unzip |
the command used unzipping help files. |
de.cellwidth |
integer: the cell widths (number of characters)
to be used in the data editor dataentry . If this is
unset, 0, negative or NA , variable cell widths are used. |
encoding |
An integer vector of length 256 holding an input
encoding. Defaults to native.enc (= 0:255 ).
See connections . |
timeout |
Integer. The timeout for Internet operations, in seconds. Default 60 seconds. |
internet.info |
The minimum level of information to be printed on url downloads etc. Default is 2, for failure causes. Set to 1 or 0 to get more information. |
x |
a character string holding one of the above option names. |
Invoking options()
with no arguments returns a list with the
current values of the options. 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, for
S compatibility. You must use it ``read only'' however.
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 | warn | 0 |
echo | TRUE | verbose | FALSE |
Others are set from environment variables or are platform-dependent.
A list (in any case) with the previous values of the options changed, or all options when no arguments were given.
options() # printing all current options op <- options(); str(op) # nicer printing # .Options is the same: all(sapply(1:length(op), function(i) all(.Options[[i]] == op[[i]]))) 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(op) # reset (all) initial options options('digits') ## set contrast handling to be like S options(contrasts=c("contr.helmert", "contr.poly")) ## on error, terminate the R session with error status 66 options(error=quote(q("no", status=66, runLast=FALSE))) stop("test it") ## set an error action for debugging: see ?debugger. options(error=quote(dump.frames())) ## A possible setting for non-interactive sessions options(error=quote({dump.frames(to.file=TRUE); q()}))