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

Arguments

[any] Object to check.

na.ok

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

min.chars

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

pattern

[character(1L)] Regular expression as used in grepl. All 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 elements of x mus

ignore.case

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

add

[AssertCollection] Collection to store assertions. See AssertCollection.

.var.name

[character(1)] Name for x. Defaults to a heuristic to determine the name using deparse and substitute.

info

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

label

[character(1)] Same as .var.name, but passed down to expect_that.

Value

Depending on the function prefix: If the check is successful, the functions 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.

Examples

Run this code

testString("a")
testString(letters)

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