assert_filter_cond: Is an Argument a Filter Condition?

Description

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()
)

Value

Performs necessary checks and returns arg if all pass. Otherwise throws an informative error.

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 form enexpr(<argument name>), the enexpr() part is removed. For example if arg = enexpr(filter_add) is specified, arg_name defaults to "filter_add"

message

string passed to cli::cli_abort(message). When NULL, 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.

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

Run this code

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)

try(assert_filter_cond(mtcars))