From ||u|@@rev|||@ @end|ng |rom gm@||@com  Tue Apr 12 09:16:36 2022
From: ||u|@@rev|||@ @end|ng |rom gm@||@com (=?UTF-8?Q?Llu=C3=ADs_Revilla?=)
Date: Tue, 12 Apr 2022 09:16:36 +0200
Subject: [Rd] intersect() change of behavior in 4.2
In-Reply-To: <CABtg=K=tRMdLJ7p2JHdFyOYVyjmLNszQguKn569gx+FswChtyw@mail.gmail.com>
References: <CABtg=K=tRMdLJ7p2JHdFyOYVyjmLNszQguKn569gx+FswChtyw@mail.gmail.com>
Message-ID: <CAN+W6_tM=+E6nCqDq9JiJ=1Gp3E=R4QFcPc06mbFyCZzWjhASQ@mail.gmail.com>

Hi all,

This change is documented on the man page so I think it is intentional.
>From https://search.r-project.org/R/refmans/base/html/sets.html:

    For union, a vector of a common mode.
    For intersect, a vector of a common mode, or NULL if x or y is NULL.
    For setdiff, a vector of the same mode as x.

Now the results are symmetrical to intersect( "foo", list())
Probably it is worth mentioning in the NEWS as it was found to cause
some test to fail on a Bioconductor package some months ago.
This could affect other packages and analysis too.

Best,

Llu?s


On Tue, 12 Apr 2022 at 01:22, G?bor Cs?rdi <csardi.gabor at gmail.com> wrote:
>
> I wonder if this change is intentional, and if it is, whether it is
> worth mentioning in the NEWS.
>
> ? R-4.1 -q -e 'intersect(list(), "foo")'
> > intersect(list(), "foo")
> character(0)
>
> ? R-4.2 -q -e 'intersect(list(), "foo")'
> > intersect(list(), "foo")
> list()
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel



[Rd] intersect() change of behavior in 4.2
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