Options

Temporarily change global options.

Usage

with_options(new, code)

local_options(.new = list(), ..., .local_envir = parent.frame())

Arguments

new, .new

[named list]
New options and their values

code

[any]
Code to execute in the temporary environment

...

Additional options and their values

.local_envir

[environment]
The environment to use for scoping.

Value

[any]
The results of the evaluation of the code argument.

See also

withr for examples

options()

Examples

# number of significant digits to print
getOption("digits")
#> [1] 7
# modify temporarily the number of significant digits to print
with_options(list(digits = 3), getOption("digits"))
#> [1] 3
with_options(list(digits = 3), print(pi))
#> [1] 3.14

# modify temporarily the character to be used as the decimal point
getOption("digits")
#> [1] 7
with_options(list(OutDec = ","), print(pi))
#> [1] 3,141593

# modify temporarily multiple options
with_options(list(OutDec = ",", digits = 3), print(pi))
#> [1] 3,14

# modify, within the scope of the function, the number of
# significant digits to print
print_3_digits <- function(x) {
  # assign 3 to the option "digits" for the rest of this function
  # after the function exits, the option will return to its previous
  # value
  local_options(list(digits = 3))
  print(x)
}

print_3_digits(pi)  # returns 3.14
#> [1] 3.14
print(pi)           # returns 3.141593
#> [1] 3.141593