R: Is the input a formula?

assert_is_formula {assertive.types}

R Documentation

Is the input a formula?

Description

Checks to see if the input is a formula.

Usage

assert_is_formula(x, severity = getOption("assertive.severity", "stop"))

assert_is_one_sided_formula(x, severity = getOption("assertive.severity",
  "stop"))

assert_is_two_sided_formula(x, severity = getOption("assertive.severity",
  "stop"))

is_formula(x, .xname = get_name_in_parent(x))

is_one_sided_formula(x, .xname = get_name_in_parent(x))

is_two_sided_formula(x, .xname = get_name_in_parent(x))

Arguments

`x`	Input to check.
`severity`	How severe should the consequences of the assertion be? Either `"stop"`, `"warning"`, `"message"`, or `"none"`.
`.xname`	Not intended to be used directly.

Value

The is_* functions return TRUE when the input is a formula. The assert_* functions return nothing but throw an error if the corresponding is_* function returns FALSE.

Examples

is_one_sided_formula(~ x)
is_two_sided_formula(y ~ x)