stabilize_chr: Ensure a character argument meets expectations
In stbl: Stabilize Function Arguments

stabilize_chr

R Documentation

Ensure a character argument meets expectations

Description

to_chr() checks whether an argument can be coerced to character without losing information, returning it silently if so. Otherwise an informative error message is signaled. to_character is a synonym of to_chr().

stabilize_chr() can check more details about the argument, but is slower than to_chr(). stabilise_chr(), stabilize_character(), and stabilise_character() are synonyms of stabilize_chr().

stabilize_chr_scalar() and to_chr_scalar() are optimized to check for length-1 character vectors. stabilise_chr_scalar, stabilize_character_scalar(), and stabilise_character_scalar are synonyms of stabilize_chr_scalar(), and to_character_scalar() is a synonym of to_chr_scalar().

Usage

stabilize_chr(
  x,
  ...,
  allow_null = TRUE,
  allow_na = TRUE,
  min_size = NULL,
  max_size = NULL,
  regex = NULL,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

stabilize_character(
  x,
  ...,
  allow_null = TRUE,
  allow_na = TRUE,
  min_size = NULL,
  max_size = NULL,
  regex = NULL,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

stabilise_chr(
  x,
  ...,
  allow_null = TRUE,
  allow_na = TRUE,
  min_size = NULL,
  max_size = NULL,
  regex = NULL,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

stabilise_character(
  x,
  ...,
  allow_null = TRUE,
  allow_na = TRUE,
  min_size = NULL,
  max_size = NULL,
  regex = NULL,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

stabilize_chr_scalar(
  x,
  ...,
  allow_null = FALSE,
  allow_zero_length = FALSE,
  allow_na = TRUE,
  regex = NULL,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

stabilize_character_scalar(
  x,
  ...,
  allow_null = FALSE,
  allow_zero_length = FALSE,
  allow_na = TRUE,
  regex = NULL,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

stabilise_chr_scalar(
  x,
  ...,
  allow_null = FALSE,
  allow_zero_length = FALSE,
  allow_na = TRUE,
  regex = NULL,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

stabilise_character_scalar(
  x,
  ...,
  allow_null = FALSE,
  allow_zero_length = FALSE,
  allow_na = TRUE,
  regex = NULL,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

to_chr(
  x,
  ...,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

to_character(
  x,
  ...,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

## S3 method for class ''NULL''
to_chr(x, ..., allow_null = TRUE, x_arg = caller_arg(x), call = caller_env())

to_chr_scalar(
  x,
  ...,
  allow_null = FALSE,
  allow_zero_length = FALSE,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

to_character_scalar(
  x,
  ...,
  allow_null = FALSE,
  allow_zero_length = FALSE,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

Arguments

`x`	The argument to stabilize.
`...`	Arguments passed to methods.
`allow_null`	`⁠(length-1 logical)⁠` Is NULL an acceptable value?
`allow_na`	`⁠(length-1 logical)⁠` Are NA values ok?
`min_size`	`⁠(length-1 integer)⁠` The minimum size of the object. Object size will be tested using `vctrs::vec_size()`.
`max_size`	`⁠(length-1 integer)⁠` The maximum size of the object. Object size will be tested using `vctrs::vec_size()`.
`regex`	`⁠(character, list, or stringr_pattern)⁠` One or more optional regular expressions to test against the values of `x`. This can be a character vector, a list of character vectors, or a pattern object from the {stringr} package (e.g., `stringr::fixed("a.b")`). The default error message for non-matching values will include the pattern itself (see `regex_must_match()`). To provide a custom message, supply a named character vector where the value is the regex pattern and the name is the message that should be displayed. To check that a pattern is not matched, attach a `negate` attribute set to `TRUE`. If a complex regex pattern throws an error, try installing the stringi package.
`x_arg`	`⁠(length-1 character)⁠` The name of the argument being stabilized to use in error messages. The automatic value will work in most cases, or pass it through from higher-level functions to make error messages clearer in unexported functions.
`call`	`(environment)` The execution environment to mention as the source of error messages.
`x_class`	`⁠(length-1 character)⁠` The class name of the argument being stabilized to use in error messages. Use this if you remove a special class from the object before checking its coercion, but want the error message to match the original class.
`allow_zero_length`	`⁠(length-1 logical)⁠` Are zero-length vectors acceptable?

Details

These functions have two important differences from base::as.character():

lists and data.frames are not coerced to character. In base R, such objects are coerced to character representations of their elements. For example, as.character(list(1:3)) returns "1:10". In the unlikely event that this is the expected behavior, use as.character() instead.
NULL values can be rejected as part of the call to this function (with allow_null = FALSE).

Value

The argument as a character vector.

Examples

to_chr("a")
to_chr(letters)
to_chr(1:10)
to_chr(1 + 0i)
to_chr(NULL)
try(to_chr(NULL, allow_null = FALSE))

to_chr_scalar("a")
try(to_chr_scalar(letters))

stabilize_chr(letters)
stabilize_chr(1:10)
stabilize_chr(NULL)
try(stabilize_chr(NULL, allow_null = FALSE))
try(stabilize_chr(c("a", NA), allow_na = FALSE))
try(stabilize_chr(letters, min_size = 50))
try(stabilize_chr(letters, max_size = 20))
try(stabilize_chr(c("hide", "find", "find", "hide"), regex = "hide"))

stabilize_chr_scalar(TRUE)
stabilize_chr_scalar("TRUE")
try(stabilize_chr_scalar(c(TRUE, FALSE, TRUE)))
try(stabilize_chr_scalar(NULL))
stabilize_chr_scalar(NULL, allow_null = TRUE)

stbl documentation built on April 4, 2026, 5:06 p.m.