R: Check if an argument is a string

checkString {checkmate}

R Documentation

Check if an argument is a string

Description

A string is defined as a scalar character vector. To check for vectors of arbitrary length, see checkCharacter.

Usage

checkString(
  x,
  na.ok = FALSE,
  n.chars = NULL,
  min.chars = NULL,
  max.chars = NULL,
  pattern = NULL,
  fixed = NULL,
  ignore.case = FALSE,
  null.ok = FALSE
)

check_string(
  x,
  na.ok = FALSE,
  n.chars = NULL,
  min.chars = NULL,
  max.chars = NULL,
  pattern = NULL,
  fixed = NULL,
  ignore.case = FALSE,
  null.ok = FALSE
)

assertString(
  x,
  na.ok = FALSE,
  n.chars = NULL,
  min.chars = NULL,
  max.chars = NULL,
  pattern = NULL,
  fixed = NULL,
  ignore.case = FALSE,
  null.ok = FALSE,
  .var.name = vname(x),
  add = NULL
)

assert_string(
  x,
  na.ok = FALSE,
  n.chars = NULL,
  min.chars = NULL,
  max.chars = NULL,
  pattern = NULL,
  fixed = NULL,
  ignore.case = FALSE,
  null.ok = FALSE,
  .var.name = vname(x),
  add = NULL
)

testString(
  x,
  na.ok = FALSE,
  n.chars = NULL,
  min.chars = NULL,
  max.chars = NULL,
  pattern = NULL,
  fixed = NULL,
  ignore.case = FALSE,
  null.ok = FALSE
)

test_string(
  x,
  na.ok = FALSE,
  n.chars = NULL,
  min.chars = NULL,
  max.chars = NULL,
  pattern = NULL,
  fixed = NULL,
  ignore.case = FALSE,
  null.ok = FALSE
)

expect_string(
  x,
  na.ok = FALSE,
  n.chars = NULL,
  min.chars = NULL,
  max.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`.
`n.chars`	[`integer(1)`] Exact number of characters for each element of `x`.
`min.chars`	[`integer(1)`] Minimum number of characters for each element of `x`.
`max.chars`	[`integer(1)`] Maximum 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`.

Details

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

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/check_string return a string with the error message. The function expect_string always returns an expectation.

Examples

testString("a")
testString(letters)

[Package checkmate version 2.3.2 Index]