Assert input is a factor

Assert an R object is a factor. Note that no assert_factor function exists since in R factors are always vector quantities (never scalar / in matrices)

Usage

assert_factor_vector(
  x,
  msg = NULL,
  call = rlang::caller_env(),
  arg_name = NULL
)

Arguments

x

An object

msg

A character string containing the error message to display if x is not a factor

call

Only relevant when pooling assertions into multi-assertion helper functions. See cli_abort for details.

arg_name

Advanced use only. Name of the argument passed (default: NULL, will automatically extract arg_name).

Value

invisible(TRUE) if x is a factor, otherwise aborts with the error message specified by msg

Details

Technically this function name is misleading, since is.vector(factor(1)) == FALSE but since they act exactly like vectors to end users, I think this name is the most suitable

Examples

try({
assert_factor_vector(factor(c("a", "b", "c"))) # Passes
assert_factor_vector(c("a", "b", "c")) # Throws default error
assert_factor_vector(factor(c("a", "b", "c")), "Custom error message") # Passes
assert_factor_vector(1:3, "Custom error message") # Throws custom error
})
#> Error in eval(expr, envir) : 
#>   'c("a", "b", "c")' must be a factor, not a character