| 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(...);Options used in base R + add.smooth: typically logical, defaulting to TRUE. Could also be set to an integer for specifying how many (simulated) smooths should be added. This is currently only used by plot.lm. + askYesNo: a function (typically set by a front-end) to ask the user binary response functions in a consistent way, or a vector of strings used by askYesNo to use as default responses for such questions.
browserNLdisabled: logical: whether newline is disabled as a synonym for "n" in the browser.
checkPackageLicense: logical, not set by default. If true, loadNamespace asks a user to accept any non-standard license at first load of the package.
check.bounds: logical, defaulting to FALSE. If true, a warning is produced whenever a vector (atomic or list) is extended, by something like x <- 1:3; x[5] <- 6.
CBoundsCheck: logical, controlling whether .C and .Fortran make copies to check for array over-runs on the atomic vector arguments.
Initially set from value of the environment variable RCBOUNDS_CHECK (set to yes to enable).
conflicts.policy: character string or list controlling handling of conflicts found in calls to library or require. See library for details.
continue: a non-empty string setting the prompt used for lines which continue over one line.
defaultPackages: the packages that are attached by default when R starts up. Initially set from value of the environment variable RDEFAULTPACKAGES, or if that is unset to c("datasets", "utils", "grDevices", "graphics", "stats", "methods"). (Set RDEFAULTPACKAGES to NULL or a comma-separated list of package names.) It will not work to set this in a ‘.Rprofile’ file, as its value is consulted before that file is read.
deparse.cutoff: integer value controlling the printing of language constructs which are deparsed. Default 60.
deparse.max.lines: controls the number of lines used when deparsing in traceback, browser, and upon entry to a function whose debugging flag is set. Initially unset, and only used if set to a positive integer.
digits: controls the number of significant (see signif) digits to print when printing numeric values. It is a suggestion only. Valid values are 1...22 with default 7. See the note in print.default about values greater than 15.
digits.secs: controls the maximum number of digits to print when formatting time values in seconds. Valid values are 0...6 with default 0. See strftime.
download.file.extra: Extra command-line argument(s) for non-default methods: see download.file.
download.file.method: Method to be used for download.file. Currently download methods "internal", "wininet" (Windows only), "libcurl", "wget" and "curl" are available. If not set, method = "auto" is chosen: see download.file.
echo: logical. Only used in non-interactive mode, when it controls whether input is echoed. Command-line option --slave sets this to FALSE, but otherwise it starts the session as TRUE.
encoding: The name of an encoding, default "native.enc". See connections.
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. By default the option is not set: see stop for the behaviour in that case. The functions dump.frames and recover provide alternatives that allow post-mortem debugging. Note that these need to specified as e.g. options(error = utils::recover) in startup files such as ‘.Rprofile’.
expressions: sets a limit on the number of nested expressions that will be evaluated. Valid values are 25...500000 with default 5000. If you increase it, you may also want to start R with a larger protection stack; see --max-ppsize in Memory. Note too that you may cause a segfault from overflow of the C stack, and on OSes where it is possible you may want to increase that. Once the limit is reached an error is thrown. The current number under evaluation can be found by calling Cstack_info.
interrupt: a function taking no arguments to be called on a user interrupt if the interrupt condition is not otherwise handled.
keep.parse.data: When internally storing source code (keep.source is TRUE), also store parse data. Parse data can then be retrieved with getParseData() and used e.g. for spell checking of string constants or syntax highlighting. The value has effect only when internally storing source code (see keep.source). The default is TRUE.
keep.parse.data.pkgs: As for keep.parse.data, used only when packages are installed. Defaults to FALSE unless the environment variable RKEEPPKGPARSEDATA is set to yes. The space overhead of parse data can be substantial even after compression and it causes performance overhead when loading packages.
keep.source: When TRUE, the source code for functions (newly defined or loaded) is stored internally allowing comments to be kept in the right places. Retrieve the source by printing or using deparse(fn, control = "useSource").
The default is interactive(), i.e., TRUE for interactive use.
keep.source.pkgs: As for keep.source, used only when packages are installed. Defaults to FALSE unless the environment variable RKEEPPKG_SOURCE is set to yes.
matprod: a string selecting the implementation of the matrix products %*%, crossprod, and tcrossprod for double and complex vectors:
"internal" uses an unoptimized 3-loop algorithm which correctly propagates NaN and Inf values and is consistent in precision with other summation algorithms inside R like sum or colSums (which now means that it uses a long double accumulator for summation if available and enabled, see capabilities).
"default" uses BLAS to speed up computation, but to ensure correct propagation of NaN and Inf values it uses an unoptimized 3-loop algorithm for inputs that may contain NaN or Inf values. When deemed beneficial for performance, "default" may call the 3-loop algorithm unconditionally, i.e., without checking the input for NaN/Inf values. The 3-loop algorithm uses (only) a double accumulator for summation, which is consistent with the reference BLAS implementation.
"blas" uses BLAS unconditionally without any checks and should be used with extreme caution. BLAS libraries do not propagate NaN or Inf values correctly and for inputs with NaN/Inf values the results may be undefined.
"default.simd" is experimental and will likely be removed in future versions of R. It provides the same behavior as "default", but the check whether the input contains NaN/Inf values is faster on some SIMD hardware. On older systems it will run correctly, but may be much slower than "default".
max.print: integer, defaulting to 99999. print or show methods can make use of this option, to limit the amount of information that is printed, to something in the order of (and typically slightly less than) max.print entries.
OutDec: character string containing a single character. The preferred character to be used as the decimal point in output conversions, that is in printing, plotting, format and as.character but not when deparsing nor by sprintf nor formatC (which are sometimes used prior to printing.)
pager: the command used for displaying text files by file.show, details depending on the platform:
On a unix-alike defaults to ‘R_HOME/bin/pager’, which is a shell script running the command-line specified by the environment variable PAGER whose default is set at configuration, usually to less.
On Windows defaults to "internal", which uses a pager similar to the GUI console. Another possibility is "console" to use the console itself.
Can be a character string or an R function, in which case it needs to accept the arguments (files, header, title, delete.file) corresponding to the first four arguments of file.show.
papersize: the default paper format used by postscript; set by environment variable R_PAPERSIZE when R is started: if that is unset or invalid it defaults platform dependently
on a unix-alike to a value derived from the locale category LC_PAPER, or if that is unavailable to a default set when R was built.
on Windows to "a4", or "letter" in US and Canadian locales.
PCRElimitrecursion: Logical: should grep(perl = TRUE) and similar limit the maximal recursion allowed when matching? PCRE can be built not to use a recursion stack (see pcre_config, but it is by default with a recursion limit of 10000000 which potentially needs a very large C stack: see the discussion at http://www.pcre.org/original/doc/html/pcrestack.html.If true, the limit is reduced using R's estimate of the C stack size available (if known), otherwise 10000. If NA, the limit is imposed only if any input string has 1000 or more bytes.
PCRE_study: Logical or integer: should grep(perl = TRUE) and similar ‘study’ the patterns? Either logical or a numerical threshold for the minimum number of strings to be matched for the pattern to be studied (the default is 10)). Missing values and negative numbers are treated as false.
PCREuseJIT: Logical: should grep(perl = TRUE), strsplit(perl = TRUE) and similar make use of PCRE's Just-In-Time compiler for studied patterns, if available? Missing values are treated as false.
pdfviewer: default PDF viewer. The default is set from the environment variable R_PDFVIEWER, the default value of which
on a unix-alike is set when R is configured, and
on Windows is the full path to open.exe, a utility supplied with R.
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. Usually set to "lpr" on a Unix-alike.
prompt: a non-empty string to be used for R's prompt; should usually end in a blank (" ").
rlwordbreaks: (Unix only:) Used for the readline-based terminal interface. Default value " \t\n\"\\'`><=%;,|&{()}".
This is the set of characters use to break the input line into tokens for
object- and file-name completion. Those who do not use spaces around
operators may prefer
" \t\n\"\\'`><=+-*%;,|&{()}"
save.defaults, save.image.defaults: see save.
scipen: integer. A penalty to be applied when deciding to print numeric values in fixed or exponential notation. Positive values bias towards fixed and negative towards scientific notation: fixed notation will be preferred unless it is more than scipen digits wider.
setWidthOnResize: a logical. If set and TRUE, R run in a terminal using a recent readline library will set the width option when the terminal is resized.
showWarnCalls, showErrorCalls: a logical. Should warning and error messages show a summary of the call stack? By default error calls are shown in non-interactive sessions.
showNCalls: integer. Controls how long the sequence of calls must be (in bytes) before ellipses are used. Defaults to 40 and should be at least 30 and no more than 500.
show.error.locations: Should source locations of errors be printed? If set to TRUE or "top", the source location that is highest on the stack (the most recent call) will be printed. "bottom" will print the location of the earliest call found on the stack.
Integer values can select other entries. The value 0 corresponds to "top" and positive values count down the stack from there. The value -1 corresponds to "bottom" and negative values count up from there.
show.error.messages: a logical. Should error messages be printed? Intended for use with try or a user-installed error handler.
stringsAsFactors: The default setting for arguments of data.frame and read.table.
texi2dvi: used by functions texi2dvi and texi2pdf in package tools.
unix-alike only: Set at startup from the environment variable R_TEXI2DVICMD, which defaults first to the value of environment variable TEXI2DVI, and then to a value set when R was installed (the full path to a texi2dvi script if one was found). If necessary, that environment variable can be set to "emulation".
timeout: integer. The timeout for some Internet operations, in seconds. Default 60 seconds. See download.file and connections.
topLevelEnvironment: see topenv and sys.source.
url.method: character string: the default method for url. Normally unset, which is equivalent to "default", which is "internal" except on Windows.
useFancyQuotes: controls the use of directional quotes in sQuote, dQuote and in rendering text help (see Rd2txt in package tools). Can be TRUE, FALSE, "TeX" or "UTF-8".
verbose: logical. Should R report extra information on progress? Set to TRUE by the command-line option --verbose.
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 top–level function returns. If 10 or fewer warnings were signalled they will be printed otherwise a message saying how many were signalled. An object called last.warning is created and can be printed through the function warnings. If warn is one, warnings are printed as they occur. If warn is two (or larger, coercible to integer), all warnings are turned into errors.
warnPartialMatchArgs: logical. If true, warns if partial matching is used in argument matching.
warnPartialMatchAttr: logical. If true, warns if partial matching is used in extracting attributes via attr.
warnPartialMatchDollar: logical. If true, warns if partial matching is used for extraction by $.
warning.expression: an R code expression to be called if a warning is generated, replacing the standard message. If non-null it is called irrespective of the value of option warn.
warning.length: sets the truncation limit for error and warning messages. A non-negative integer, with allowed values 100...8170, default 1000.
nwarnings: the limit for the number of warnings kept when warn = 0, default 50. This will discard messages if called whilst they are being collected. If you increase this limit, be aware that the current implementation pre-allocates the equivalent of a named list for them, i.e., do not increase it to more than say a million.
width: controls the maximum number of columns on a line used in printing vectors, matrices and arrays, and when filling by cat.
Columns are normally the same as characters except in East Asian languages.
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 limits on valid values are in file ‘Print.h’ and can be changed by re-compiling R.) Some R consoles automatically change the value when they are resized.
See the examples on Startup for one way to set this automatically from the terminal width when R is started.
The ‘factory-fresh’ default settings of some of these options are
add.smooth TRUE check.bounds FALSE continue "+ " digits 7 echo TRUE encoding "native.enc" error NULL expressions 5000 keep.source interactive() keep.source.pkgs FALSE max.print 99999 OutDec "." prompt "> " scipen 0 show.error.messages TRUE timeout 60 verbose FALSE warn 0 warning.length 1000 width 80 Others are set from environment variables or are platform-dependent.
For options(), a list of all set options sorted by name. For options(name), a list of length one containing the set value, or NULL if it is unset. For uses setting one or more options, a list with the previous values of the options changed (returned invisibly).