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System & OS

options

R Base 3.6.2

Allow the user to set and examine a variety of global options which affect the way in which R computes and displays its results.

Syntax

R 
options(&#8230;)<p></p><p>getOption(x, default = NULL)</p><p>.Options</p>

Arguments

Parameter Description
&#8230; any options can be defined, using name = value. However, only the ones below are used in base R. Options can also be passed by giving a single unnamed argument which is a named list.
x a character string holding an option name.
default if the specified option is not set in the options list, this value is returned. This facilitates retrieving an option and checking whether it is set and setting it separately if not.

Return Value

For getOption, the current value set for option x, or default (which defaults to NULL) if the option is unset. 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).

Details

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, e.g., getOption("width") rather than options("width") which is a list of length one.

Examples

Example
R 
# NOT RUN {
op <- options(); utils::str(op) # op is a named list

getOption("width") == options()$width # the latter needs more memory
options(digits = 15)
pi

# set the editor, and save previous value
old.o <- options(editor = "nedit")
old.o

options(check.bounds = TRUE, warn = 1)
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"))
# }
# 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")
# }
# NOT RUN {
# }
# NOT RUN {
## Set error actions for debugging:
## enter browser on error, see ?recover:
options(error = recover)
## allows to call debugger() afterwards, see ?debugger:
options(error = dump.frames)
## A possible setting for non-interactive sessions
options(error = quote({dump.frames(to.file = TRUE); q()}))
# }
# NOT RUN {
  # Compare the two ways to get an option and use it
  # acconting for the possibility it might not be set.
if(as.logical(getOption("performCleanp", TRUE)))
   cat("do cleanup\n")

# }
# NOT RUN {
  # a clumsier way of expressing the above w/o the default.
tmp <- getOption("performCleanup")
if(is.null(tmp))
  tmp <- TRUE
if(tmp)
   cat("do cleanup\n")
# }
# NOT RUN {
# }