These functions check whether a value was specified as an argument to a
function.
Usage
check_missing(x)
assert_missing(x)
test_missing(x)
Arguments
- x
[any]
A formal argument.
Value
Depending on the function prefix:
If the check is successful, assert_missing() returns x invisibly,
whereas check_missing() and test_missing() return TRUE.
If the check is not successful, assert_missing() throws an error message,
test_missing() returns FALSE, and check_missing() returns a string with
the error message.
See also
Other package helpers:
Dictionary,
Storage,
find_namespace_calls(),
identical_structure(),
input_check_response(),
match_arg(),
package_logo(),
print_data.frame(),
print_matrix(),
system_information(),
unexpected_error(),
user_confirm()
Examples
f <- function(x) {
check_missing(x)
}
f()
#> [1] "Argument needs a value"
g <- function(x) {
test_missing(x)
}
g()
#> [1] FALSE
h <- function(x) {
assert_missing(x)
}
if (FALSE) { # \dontrun{
h()
} # }
