Message-ID: <f144303d-0fa6-7827-bca3-2587a43c3484@mpiib-berlin.mpg.de>
Date: 2019-09-11T10:24:35Z
From: Hilmar Berger
Subject: '==' operator: inconsistency in data.frame(...) == NULL
In-Reply-To: <c21fa68d-00da-dcc1-6390-dce52c889748@mpiib-berlin.mpg.de>
Another example where a data.frame is compared to (here non-null,
non-empty) non-atomic values in Ops.data.frame, resulting in an error
message:
setClass("FOOCLASS2",
???????? slots = c(M="matrix")
)
ma = new("FOOCLASS2", M=matrix(rnorm(300), 30,10))
> isS4(ma)
[1] TRUE
> ma == data.frame(a=1:3)
Error in eval(f) : dims [product 1] do not match the length of object [3]
As for the NULL/logical(0) cases I would suggest to explicitly test for
invalid conditions in Ops.data.frame and generate a comprehensible
message (e.g. "comparison is possible only for atomic and list types")
if appropriate.
Best regards,
Hilmar
On 11/09/2019 11:55, Hilmar Berger wrote:
>
> In the data.frame()==NULL cases I have the impression that the fact
> that both sides are non-atomic is not properly detected and therefore
> R tries to go on with the == method for data.frames.
>
> From a cursory check in Ops.data.frame() and some debugging I have the
> impression that the case of the second argument being non-atomic or
> empty is not handled at all and the function progresses until the end,
> where it fails in the last step on an empty value:
>
> matrix(unlist(value, recursive = FALSE, use.names = FALSE),
> ??? nrow = nr, dimnames = list(rn, cn))
--
Dr. Hilmar Berger, MD
Max Planck Institute for Infection Biology
Charit?platz 1
D-10117 Berlin
GERMANY
Phone: + 49 30 28460 430
Fax: + 49 30 28460 401
E-Mail: berger at mpiib-berlin.mpg.de
Web : www.mpiib-berlin.mpg.de