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Does this object inherit from a class?

Source: R/inherits.R
S7_inherits.Rd

  • S7_inherits() returns TRUE or FALSE.

  • check_is_S7() throws an error if x isn't the specified class.

Usage

S7_inherits(x, class = NULL)

check_is_S7(
  x,
  class = NULL,
  arg = deparse(substitute(x)),
  call = sys.call(-1L)
)

Arguments

x

An object.

class

A class specification (anything accepted by as_class(): an S7 class, S7 union, S3 class, S4 class, base type wrapper like class_integer, or class_any/class_missing). If NULL, only tests whether x is an S7 object, without testing for a specific class.

arg

Argument name used in error message.

call

The call to report in the error message. Defaults to the calling function.

Value

  • S7_inherits() returns a single TRUE or FALSE.

  • check_is_S7() returns nothing; it's called for its side-effects.

Note

Starting with R 4.3.0, base::inherits() can accept an S7 class as the second argument, supporting usage like inherits(x, Foo).

Examples

Foo1 <- new_class("Foo1")
Foo2 <- new_class("Foo2")

S7_inherits(Foo1(), Foo1)
#> [1] TRUE
check_is_S7(Foo1())
check_is_S7(Foo1(), Foo1)

S7_inherits(Foo1(), Foo2)
#> [1] FALSE
try(check_is_S7(Foo1(), Foo2))
#> Error in try(check_is_S7(Foo1(), Foo2)) : 
#>   `Foo1()` must be a <Foo2>, not a <Foo1>.

# Also works with other class specifications
S7_inherits(1L, class_integer)
#> [1] TRUE
S7_inherits(data.frame(), new_S3_class("data.frame"))
#> [1] TRUE
S7_inherits(1L, class_integer | class_character)
#> [1] TRUE

if (getRversion() >= "4.3.0") {
  inherits(Foo1(), Foo1)
}
#> [1] TRUE