is.null.DN | R Documentation |
dn
NULL-like ?Are the dimnames
dn
NULL
-like?
is.null.DN(dn)
is less strict than is.null(dn)
,
because it is also true (TRUE
) when the dimnames
dn
are “like” NULL
, or list(NULL,NULL)
, as
they can easily be for the traditional R matrices
(matrix
) which have no formal class
definition, and hence much freedom in how their dimnames
look like.
is.null.DN(dn)
dn |
|
logical
TRUE
or FALSE
.
This function is really to be used on “traditional” matrices
rather than those inheriting from Matrix
, as
the latter will always have dimnames list(NULL,NULL)
exactly,
in such a case.
Martin Maechler
is.null
,
dimnames
, matrix
.
m <- matrix(round(100 * rnorm(6)), 2,3); m1 <- m2 <- m3 <- m4 <- m dimnames(m1) <- list(NULL, NULL) dimnames(m2) <- list(NULL, character()) dimnames(m3) <- rev(dimnames(m2)) dimnames(m4) <- rep(list(character()),2) m4 ## prints absolutely identically to m stopifnot(m == m1, m1 == m2, m2 == m3, m3 == m4, identical(capture.output(m) -> cm, capture.output(m1)), identical(cm, capture.output(m2)), identical(cm, capture.output(m3)), identical(cm, capture.output(m4))) hasNoDimnames <- function(.) is.null.DN(dimnames(.)) stopifnot(exprs = { hasNoDimnames(m) hasNoDimnames(m1); hasNoDimnames(m2) hasNoDimnames(m3); hasNoDimnames(m4) hasNoDimnames(Matrix(m) -> M) hasNoDimnames(as(M, "sparseMatrix")) })
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