NULL
The Null Object
Description
Coerces or tests for NULL objects.
Usage
as.null(x, ...)
as.null.default(x, ...)
is.null(x)
Arguments
| x |
any object.
|
| ... |
other optional arguments to pass to or from the method.
Reserved for future use.
|
Details
Both is.null and as.null are generic. Currently,
only as.null has defined a default method.
Value
| as.null | always returns NULL. |
| is.null | returns TRUE if x is NULL
and returns FALSE if x is not NULL. |
Warning
An object can be of length 0 and not be NULL. See
the examples section.
See Also
Examples
is.null(character(0)) # returns FALSE
as.null(list(a=1:5, b=1:10))