| NULL {base} | R Documentation |
The Null Object
Description
NULL represents the null object in R: it is a reserved word.
NULL is often returned by expressions and functions whose
value is undefined: it is also used as the empty pairlist.
as.null ignores its argument and returns the value NULL.
is.null returns TRUE if its argument
is NULL and FALSE otherwise.
Usage
NULL
as.null(x, ...)
is.null(x)
Arguments
x |
an object to be tested or coerced. |
... |
ignored. |
References
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
Examples
is.null(list()) # FALSE (on purpose!)
is.null(integer(0))# F
is.null(logical(0))# F
as.null(list(a=1,b='c'))