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Coerce to length-1 character with additional checks

Source: R/stabilize_chr.R
stabilize_chr_scalar.Rd

Checks whether a vector can be coerced to a length-1 character vector. stabilize_chr_scalar() is optimized to check for length-1 character vectors (compared to stabilize_chr() with max_size = 1). stabilise_chr_scalar, stabilize_character_scalar(), and stabilise_character_scalar are synonyms of stabilize_chr_scalar().

Usage

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

Arguments

x

The object to stabilize.

...

Arguments passed to methods.

allow_null

(logical(1)) Is NULL an acceptable value?

allow_zero_length

(logical(1)) Are zero-length vectors acceptable?

allow_na

(logical(1)) Are NA values ok?

min_characters

(integer(1)) Minimum number of characters allowed in each element.

max_characters

(integer(1)) Maximum number of characters allowed in each element.

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.

allowed_values

A vector of permitted values (coerced to the target type). NULL (default) skips the check. NA values in x are permitted independently of allowed_values, subject to allow_na.

x_arg

(character(1)) The name of the object 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

(character(1)) The class name of the object 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.

Value

The input as a length-1 character vector, or an error condition with classes <stbl-error>, <stbl-condition>, <rlang_error>, <error>, <condition>, and a specific class by failure mode:

  • <stbl-error-coerce-character> when x cannot be coerced to character.

  • <stbl-error-bad_null> for NULL values when allow_null = FALSE.

  • <stbl-error-bad_empty> for empty vectors when allow_zero_length = FALSE.

  • <stbl-error-non_scalar> for non-scalar vectors.

  • <stbl-error-bad_na> for NA values when allow_na = FALSE.

  • <stbl-error-n_characters-too_few> when the element has fewer characters than min_characters.

  • <stbl-error-n_characters-too_many> when the element has more characters than max_characters.

  • <stbl-error-regex_mismatch> when regex checks fail.

  • <stbl-error-allowed_values> when the value is not in allowed_values.

See also

Other character functions: are_chr_ish(), specify_chr(), stabilize_chr(), to(), to_chr(), to_chr_scalar()

Other stabilization functions: assert_present(), stabilize_any_of(), stabilize_arg(), stabilize_chr(), stabilize_date(), stabilize_date_scalar(), stabilize_dbl(), stabilize_dbl_scalar(), stabilize_df(), stabilize_dttm(), stabilize_dttm_scalar(), stabilize_dur(), stabilize_dur_scalar(), stabilize_fct(), stabilize_fct_scalar(), stabilize_int(), stabilize_int_scalar(), stabilize_lgl(), stabilize_lgl_scalar(), stabilize_lst(), stabilize_time(), stabilize_time_scalar(), to_chr(), to_chr_scalar(), to_date(), to_date_scalar(), to_dbl(), to_dbl_scalar(), to_dttm(), to_dttm_scalar(), to_dur(), to_dur_scalar(), to_fct(), to_fct_scalar(), to_int(), to_int_scalar(), to_lgl(), to_lgl_scalar(), to_time(), to_time_scalar()

Examples

stabilize_chr_scalar(TRUE)
#> [1] "TRUE"
try(stabilize_chr_scalar(c(TRUE, FALSE, TRUE)))
#> Error in eval(expr, envir) : 
#>   `c(TRUE, FALSE, TRUE)` must be a single <character>.
#> ✖ `c(TRUE, FALSE, TRUE)` has 3 values.
try(stabilize_chr_scalar(NULL))
#> Error in eval(expr, envir) : `NULL` must not be <NULL>.
stabilize_chr_scalar(NULL, allow_null = TRUE)
#> NULL