assert_vars: Is an Argument a List of Variables?
In epijim/admiral: ADaM in R Asset Library

Description Usage Arguments Value Author(s) Examples

Checks if an argument is a valid list of variables created using vars()

1	assert_vars(arg, optional = FALSE)

`arg`	A function argument to be checked
`optional`	Is the checked parameter optional? If set to `FALSE` and `arg` is `NULL` then an error is thrown

The function throws an error if arg is not a list of variables created using vars() and returns the input invisibly otherwise.

Samia Kabi

example_fun <- function(by_vars) {
  assert_vars(by_vars)
}

example_fun(vars(USUBJID, PARAMCD))

try(example_fun(exprs(USUBJID, PARAMCD)))

try(example_fun(c("USUBJID", "PARAMCD", "VISIT")))

try(example_fun(vars(USUBJID, toupper(PARAMCD), desc(AVAL))))