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Check if Argument is of Proper Length

Source: R/check_length.R
check_length.Rd

TODO.

Usage

check_length(x, arg_length = 1L, alt_null = FALSE, add_msg = NULL)

Arguments

x

Function arguments that are being asserted.

arg_length

Integer. Length of argument, for scalars it should take value 1 (default).

alt_null

Logical. Should argument accept NULL value.

add_msg

Is an additional message that can be printed over the standard function error message. You can:

  • pass the names of the arguments that failed the test by using {x_name} in the message body (e.g. "What are the {wrong_names}");

  • pass the tested length by using {arg_length} in the message body (e.g. "I want them to be {arg_length})"

  • pass the lengths of the arguments that failed the test by using {wrong_length} in the message body (e.g. "{wrong_lengths} are wrong")

Value

Returns invisible NULL when argument is of asserted length, otherwise it will throw an error.

Examples

x1 <- 2
x2 <- c("x", "y")
nl1 <- NULL
if (FALSE) { # \dontrun{
check_length(x1, arg_length = 1L)
check_length(x2, arg_length = 1L)
check_length(x1, arg_length = 2L)
check_length(
  x1, arg_length = 2L, add_msg = "{.arg {x_name}} should be short"
)
check_length(
  x1, arg_length = 2L, alt_null = TRUE, add_msg = "{.arg {x_name}} should be short"
)
check_length(
  nl1, arg_length = 2L, alt_null = TRUE, add_msg = "{.arg {x_name}} should be short"
)
} # }