is.function {base} | R Documentation

## Is an Object of Type (Primitive) Function?

### Description

Checks whether its argument is a (primitive) function.

### Usage

    is.function(x)
    is.primitive(x)

### Arguments

`x` | an R object.

### Details

`is.function` is generic: you can write methods to handle specific classes of objects, see InternalMethods.

`is.primitive(x)` tests if `x` is a primitive function (either a `"builtin"` or `"special"` as from `typeof`)?

### Value

`TRUE` if `x` is a (primitive) function, and `FALSE` otherwise.

### Examples

    is.function(1) # FALSE
    is.function(is.primitive)  # TRUE: it is a function, but ..
    is.primitive(is.primitive) # FALSE:it's not a primitive one, whereas
    is.primitive(is.function)  # TRUE: that one *is*

[Package base version 2.3.1 Index]