checkmate (version 1.8.3)

checkString: Check if an argument is a string

Description

A string is defined as a scalar character vector.

Usage

checkString(x, na.ok = FALSE, min.chars = NULL, pattern = NULL,
  fixed = NULL, ignore.case = FALSE, null.ok = FALSE)
check_string(x, na.ok = FALSE, min.chars = NULL, pattern = NULL,
  fixed = NULL, ignore.case = FALSE, null.ok = FALSE)
assertString(x, na.ok = FALSE, min.chars = NULL, pattern = NULL,
  fixed = NULL, ignore.case = FALSE, null.ok = FALSE,
  .var.name = vname(x), add = NULL)
assert_string(x, na.ok = FALSE, min.chars = NULL, pattern = NULL,
  fixed = NULL, ignore.case = FALSE, null.ok = FALSE,
  .var.name = vname(x), add = NULL)
testString(x, na.ok = FALSE, min.chars = NULL, pattern = NULL,
  fixed = NULL, ignore.case = FALSE, null.ok = FALSE)
test_string(x, na.ok = FALSE, min.chars = NULL, pattern = NULL,
  fixed = NULL, ignore.case = FALSE, null.ok = FALSE)
expect_string(x, na.ok = FALSE, min.chars = NULL, pattern = NULL,
  fixed = NULL, ignore.case = FALSE, null.ok = FALSE, info = NULL,
  label = vname(x))

Arguments

x

[any] Object to check.

na.ok

[logical(1)] Are missing values allowed? Default is FALSE.

min.chars

[integer(1)] Minimum number of characters for each element of x.

pattern

[character(1L)] Regular expression as used in grepl. All non-missing elements of x must comply to this pattern.

fixed

[character(1)] Substring to detect in x. Will be used as pattern in grepl with option fixed set to TRUE. All non-missing elements of x must contain this substring.

ignore.case

[logical(1)] See grepl. Default is FALSE.

null.ok

[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.

.var.name

[character(1)] Name of the checked object to print in assertions. Defaults to the heuristic implemented in vname.

add

[AssertCollection] Collection to store assertion messages. See AssertCollection.

info

[character(1)] Extra information to be included in the message for the testthat reporter. See expect_that.

label

[character(1)] Name of the checked object to print in messages. Defaults to the heuristic implemented in vname.

Value

Depending on the function prefix: If the check is successful, the functions assertString/assert_string return x invisibly, whereas checkString/check_string and testString/test_string return TRUE. If the check is not successful, assertString/assert_string throws an error message, testString/test_string returns FALSE, and checkString returns a string with the error message. The function expect_string always returns an expectation.

Details

This function does not distinguish between NA, NA_integer_, NA_real_, NA_complex_ NA_character_ and NaN.

See Also

Other scalars: checkCount, checkFlag, checkInt, checkNumber, checkScalarNA, checkScalar

Examples

testString("a")
testString(letters)