R: Is an Argument a Character Vector?

assert_character_vector {admiraldev}

R Documentation

Is an Argument a Character Vector?

Description

Checks if an argument is a character vector

Usage

assert_character_vector(
  arg,
  values = NULL,
  named = FALSE,
  optional = FALSE,
  arg_name = rlang::caller_arg(arg),
  message = NULL,
  class = "assert_character_vector",
  call = parent.frame()
)

Arguments

`arg`	A function argument to be checked
`values`	A `character` vector of valid values for `arg`
`named`	If set to `TRUE`, an error is issued if not all elements of the vector are named.
`optional`	Is the checked argument optional? If set to `FALSE` and `arg` is `NULL` then an error is thrown
`arg_name`	string indicating the label/symbol of the object being checked.
`message`	string passed to `cli::cli_abort(message)`. When `NULL`, default messaging is used (see examples for default messages). `"{arg_name}"` can be used in messaging.
`class`	Subclass of the condition.
`call`	The execution environment of a currently running function, e.g. `call = caller_env()`. The corresponding function call is retrieved and mentioned in error messages as the source of the error. You only need to supply `call` when throwing a condition from a helper function which wouldn't be relevant to mention in the message. Can also be `NULL` or a defused function call to respectively not display any call or hard-code a code to display. For more information about error calls, see Including function calls in error messages.

Value

The function throws an error if arg is not a character vector or if any element is not included in the list of valid values. Otherwise, the input is returned invisibly.

Checks for valid input and returns warning or errors messages: assert_atomic_vector(), assert_character_scalar(), assert_data_frame(), assert_date_vector(), assert_expr(), assert_expr_list(), assert_filter_cond(), assert_function(), assert_integer_scalar(), assert_list_element(), assert_list_of(), assert_logical_scalar(), assert_named(), assert_numeric_vector(), assert_one_to_one(), assert_param_does_not_exist(), assert_s3_class(), assert_same_type(), assert_symbol(), assert_unit(), assert_vars(), assert_varval_list()

Examples

example_fun <- function(chr) {
  assert_character_vector(chr)
}

example_fun(letters)

try(example_fun(1:10))

example_fun2 <- function(chr) {
  assert_character_vector(chr, named = TRUE)
}

try(example_fun2(c(alpha = "a", "b", gamma = "c")))