Checks if an argument is an object inheriting from the S3 class specified.
Usage
assert_s3_class(
arg,
cls,
optional = FALSE,
arg_name = rlang::caller_arg(arg),
message = NULL,
class = "assert_s3_class",
call = parent.frame()
)
Arguments
- arg
A function argument to be checked
- cls
The S3 class to check for
- optional
Is the checked argument optional? If set to
FALSE
andarg
isNULL
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)
. WhenNULL
, 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 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()
,
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_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 example_fun(letters) :
#> Argument `obj` must be class <factor>, but is a character vector.
try(example_fun(1:10))
#> Error in example_fun(1:10) :
#> Argument `obj` must be class <factor>, but is an integer vector.