TITLE(NULL @@ The Null Object)
USAGE(
NULL
as.null(x)
is.null(x)
)
ALIAS(NULL)
ALIAS(as.null)
ALIAS(is.null)
DESCRIPTION(
LANG(NULL) represents the null object in R.
NULL is used mainly to represent the lists with zero length,
and is often returned by expressions and functions whose
value is undefined.
PARA
LANG(as.null) ignores its argument and returns the value LANG(NULL).
PARA
LANG(is.null) returns LANG(TRUE) if its argument
is LANG(NULL) and LANG(FALSE) otherwise.
)
