Is an Argument an Object of a Specific S3 Class? — assert_s3_class • admiraldev

Checks if an argument is an object inheriting from the S3 class specified.

Usage

assert_s3_class(arg, class, optional = FALSE)

Arguments

arg: A function argument to be checked
class: The S3 class to check for
optional: Is the checked argument optional? If set to FALSE and arg is NULL then an error is thrown

Value

The function throws an error if arg is an object which does not inherit from class. Otherwise, the input is returned invisibly.

See also

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

Examples

example_fun <- function(obj) {
  assert_s3_class(obj, "factor")
}

example_fun(as.factor(letters))

try(example_fun(letters))
#> Error in assert_s3_class(obj, "factor") : 
#>   `obj` must be an object of class 'factor' but is a character vector

try(example_fun(1:10))
#> Error in assert_s3_class(obj, "factor") : 
#>   `obj` must be an object of class 'factor' but is an integer vector