Assert that values are counts — assert

Checks that x is numeric and every value is a non-negative whole number (0, 1, 2, ...). Doubles with no fractional part (such as 3 or c(1, 2, 3)) are accepted, as are integers. The vector counterpart of assert_scalar_count(); missing, infinite, fractional, and negative values all cause the check to fail.

Usage

assert_count(
  x,
  null_ok = FALSE,
  arg = rlang::caller_arg(x),
  call = rlang::caller_env()
)

Arguments

x: Object to check.
null_ok: Single logical. If TRUE, a NULL value passes the check without error. Use this for optional arguments that default to NULL. Defaults to FALSE, so NULL is rejected unless you opt in.
arg: Name used to refer to x in error messages. Defaults to the name of the expression passed as x.
call: Environment used as the error's call context. Defaults to the calling function, so errors point at the user's code.

Value

The input x, invisibly.

Examples

assert_count(c(0, 1, 2))
assert_count(4L)