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, |
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. |
digits |
controls the number of digits to print when printing numeric values. It is a suggestion only. |
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' on UNIX. |
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. |
keep.source |
When TRUE , the default, the source code for
functions loaded by is stored in their "source" attribute,
allowing comments to be kept in the right places. This does not apply
to functions loaded by library . |
na.action |
the name of a function for treating missing values
(NA 's) for certain situations. |
papersize |
the paper format used for graphics printing; currently
read-only, set by environment variable R_PAPERSIZE , or in
`config.site'. |
printcmd |
the command used for graphics printing; currently
read-only, set by environment variable R_PRINTCMD , or in
`config.site'. |
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 |
an expression governing the handling of non-catastrophic
errors such as those generated by stop as well as by
signals and internally detected errors. The default expression 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. |
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. |
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. Defaults to "internal" when the internal unzip DLL is used. |
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.
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 |
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(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")