Does an object inherit from a set of classes?

• inherits_any() is like base::inherits() but is more explicit about its behaviour with multiple classes. If classes contains several elements and the object inherits from at least one of them, inherits_any() returns TRUE.

• inherits_all() tests that an object inherits from all of the classes in the supplied order. This is usually the best way to test for inheritance of multiple classes.

• inherits_only() tests that the class vectors are identical. It is a shortcut for identical(class(x), class).

Usage

inherits_any(x, class)

inherits_all(x, class)

inherits_only(x, class)

Arguments

x

An object to test for inheritance.

class

A character vector of classes.

Examples

obj <- structure(list(), class = c("foo", "bar", "baz"))

# With the _any variant only one class must match:
inherits_any(obj, c("foobar", "bazbaz"))
#> [1] FALSE
inherits_any(obj, c("foo", "bazbaz"))
#> [1] TRUE

# With the _all variant all classes must match:
inherits_all(obj, c("foo", "bazbaz"))
#> [1] FALSE
inherits_all(obj, c("foo", "baz"))
#> [1] TRUE

# The order of classes must match as well:
inherits_all(obj, c("baz", "foo"))
#> [1] FALSE

# inherits_only() checks that the class vectors are identical:
inherits_only(obj, c("foo", "baz"))
#> [1] FALSE
inherits_only(obj, c("foo", "bar", "baz"))
#> [1] TRUE