Is an Argument a Filter Condition?
Usage
assert_filter_cond(
arg,
optional = FALSE,
arg_name = gsub("^enexpr\\((.*)\\)$", "\\1", rlang::caller_arg(arg)),
message = NULL,
class = "assert_filter_cond",
call = parent.frame()
)
Arguments
- arg
Quosure - filtering condition.
- optional
Logical - is the argument optional? Defaults to
FALSE
.- arg_name
By default the expression specified for
arg
is used. If it is of the formenexpr(<argument name>)
, theenexpr()
part is removed. For example ifarg = enexpr(filter_add)
is specified,arg_name
defaults to"filter_add"
- 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.
Details
Check if arg
is a suitable filtering condition to be used in
functions like subset
or dplyr::filter
.
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_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_s3_class()
,
assert_same_type()
,
assert_symbol()
,
assert_unit()
,
assert_vars()
,
assert_varval_list()
Examples
library(dplyr, warn.conflicts = FALSE)
library(rlang)
dm <- dplyr::tribble(
~DOMAIN, ~STUDYID, ~USUBJID, ~AGE,
"DM", "STUDY X", "01-701-1015", 64,
"DM", "STUDY X", "01-701-1016", 65,
)
# typical usage in a function as an argument check
example_fun <- function(dat, x) {
x <- assert_filter_cond(enexpr(x), arg_name = "x")
filter(dat, !!x)
}
example_fun(dm, AGE == 64)
#> # A tibble: 1 × 4
#> DOMAIN STUDYID USUBJID AGE
#> <chr> <chr> <chr> <dbl>
#> 1 DM STUDY X 01-701-1015 64
try(assert_filter_cond(mtcars))
#> Error in eval(expr, envir) :
#> Argument `mtcars` must be a filter condition, but is a data frame