Asserts That a Parameter is Provided in the Expected Unit

Checks if a parameter (PARAMCD) in a dataset is provided in the expected unit.

assert_unit(
  dataset,
  param,
  required_unit = NULL,
  get_unit_expr,
  arg_name = rlang::caller_arg(required_unit),
  message = NULL,
  class = "assert_unit",
  call = parent.frame()
)

Arguments

dataset

Dataset to be checked

The variable PARAMCD and those used in get_unit_expr are expected.

Default value

none

param

Parameter code of the parameter to check

Default value

none

required_unit

Expected unit(s)

If the argument is set to NULL, it is checked only whether the unit is unique within the parameter.

Permitted values

A character vector or NULL

Default value

NULL

get_unit_expr

Expression used to provide the unit of param

Default value

none

arg_name

string indicating the label/symbol of the object being checked.

Default value

rlang::caller_arg(arg)

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.

Default value

NULL

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 there is more than one non-missing unit in the dataset or

• if the unit variable differs from the expected unit for any observation of the parameter in the input dataset.

Otherwise, the dataset 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_s3_class(), assert_same_type(), assert_symbol(), assert_vars(), assert_varval_list()

Examples

library(dplyr)

advs <- tribble(
  ~USUBJID, ~VSTESTCD, ~VSTRESN, ~VSSTRESU, ~PARAMCD, ~AVAL,
  "P01",    "WEIGHT",      80.1, "kg",      "WEIGHT",  80.1,
  "P02",    "WEIGHT",      85.7, "kg",      "WEIGHT",  85.7
)

assert_unit(advs, param = "WEIGHT", required_unit = "kg", get_unit_expr = VSSTRESU)

try(
  assert_unit(
    advs,
    param = "WEIGHT",
    required_unit = c("g", "mg"),
    get_unit_expr = VSSTRESU
  )
)
#> Error in eval(expr, envir) : 
#>   It is expected that "WEIGHT" has unit of "g" or "mg". In the input
#> dataset the unit is "kg".

# Checking uniqueness of unit only
advs <- tribble(
  ~USUBJID, ~VSTESTCD, ~VSTRESN, ~VSSTRESU, ~PARAMCD, ~AVAL,
  "P01",    "WEIGHT",      80.1, "kg",      "WEIGHT",  80.1,
  "P02",    "WEIGHT",     85700, "g",       "WEIGHT", 85700
)

try(
  assert_unit(advs, param = "WEIGHT", get_unit_expr = VSSTRESU)
)
#> Error in eval(expr, envir) : 
#>   Multiple units "kg" and "g" found for "WEIGHT". Please review and update
#> the units.