Check if an argument is a single atomic value
checkScalar(x, na.ok = FALSE, null.ok = FALSE)check_scalar(x, na.ok = FALSE, null.ok = FALSE)
assertScalar(x, na.ok = FALSE, null.ok = FALSE, .var.name = vname(x),
  add = NULL)
assert_scalar(x, na.ok = FALSE, null.ok = FALSE, .var.name = vname(x),
  add = NULL)
testScalar(x, na.ok = FALSE, null.ok = FALSE)
test_scalar(x, na.ok = FALSE, null.ok = FALSE)
expect_scalar(x, na.ok = FALSE, null.ok = FALSE, info = NULL,
  label = vname(x))
[any] Object to check.
[logical(1)]
Are missing values allowed? Default is FALSE.
[logical(1)]
If set to TRUE, x may also be NULL.
In this case only a type check of x is performed, all additional checks are disabled.
[character(1)]
Name of the checked object to print in assertions. Defaults to
the heuristic implemented in vname.
[AssertCollection]
Collection to store assertion messages. See AssertCollection.
[character(1)]
Extra information to be included in the message for the testthat reporter.
See expect_that.
[character(1)]
Name of the checked object to print in messages. Defaults to
the heuristic implemented in vname.
Depending on the function prefix:
 If the check is successful, the functions 
 assertScalar/assert_scalar return 
 x invisibly, whereas
 checkScalar/check_scalar and 
 testScalar/test_scalar return 
 TRUE.
 If the check is not successful, 
 assertScalar/assert_scalar
 throws an error message, 
 testScalar/test_scalar
 returns FALSE,
 and checkScalar returns a string with the error message.
 The function expect_scalar always returns an
 expectation.
This function does not distinguish between
NA, NA_integer_, NA_real_, NA_complex_
NA_character_ and NaN.
Other scalars: checkCount,
  checkFlag, checkInt,
  checkNumber, checkScalarNA,
  checkString
testScalar(1)
testScalar(1:10)
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