Check if an argument is a formula

checkFormula(x, null.ok = FALSE)

check_formula(x, null.ok = FALSE)

assertFormula(x, null.ok = FALSE, .var.name = vname(x), add = NULL)

assert_formula(x, null.ok = FALSE, .var.name = vname(x), add = NULL)

testFormula(x, null.ok = FALSE)

test_formula(x, null.ok = FALSE)

expect_formula(x, null.ok = FALSE, info = NULL, label = vname(x))

Arguments

x

[any]
Object to check.

null.ok

[logical(1)]
If set to TRUE, x may also be NULL. In this case only a type check of x is performed, all additional checks are disabled.

.var.name

[character(1)]
Name of the checked object to print in assertions. Defaults to the heuristic implemented in vname.

add

[AssertCollection]
Collection to store assertion messages. See AssertCollection.

info

[character(1)]
Extra information to be included in the message for the testthat reporter. See expect_that.

label

[character(1)]
Name of the checked object to print in messages. Defaults to the heuristic implemented in vname.

Value

Depending on the function prefix: If the check is successful, the functions assertFormula/assert_formula return x invisibly, whereas checkFormula/check_formula and testFormula/test_formula return TRUE. If the check is not successful, assertFormula/assert_formula throws an error message, testFormula/test_formula returns FALSE, and checkFormula returns a string with the error message. The function expect_formula always returns an expectation.

See also

Examples

f = Species ~ Sepal.Length + Sepal.Width checkFormula(f)
#> [1] TRUE