[R] error in duplicated() man page

[Bert Gunter]

Thanks, Martin. I missed the duplication. My apology -- old age is
asserting it's presence.

Then my response is: I think the documentation is correct as written:

> a <- matrix(rep(1:3,2), nr=3)
> a
     [,1] [,2]
[1,]    1    1
[2,]    2    2
[3,]    3    3

> duplicated(a)
[1] FALSE FALSE FALSE
> ## Note: Row major by default !

> duplicated(a, MAR = 2)
[1] FALSE  TRUE

Again, apologies for my silly error.

Cheers,
Bert



On Thu, May 9, 2019 at 8:56 AM Martin Maechler <maechler using stat.math.ethz.ch>
wrote:

> >>>>> Bert Gunter
> >>>>>     on Thu, 9 May 2019 08:46:15 -0700 writes:
>
>     > Juan:
>     > No, I think there may be a bug:
>
>     >> duplicated(array(c(1,2,3,2,5,6),c(3,2)), MARGIN=1:2)
>     > [,1]  [,2]
>     > [1,] FALSE  TRUE
>     > [2,] FALSE FALSE
>     > [3,] FALSE FALSE
>     > ## This is wrong
>
>     > ## But if we first define the array...
>     >> a <- array(c(1,2,3,4,5,6), c(3,2))
>     >> duplicated(a, MARGIN = 1:2)
>     > [,1]  [,2]
>     > [1,] FALSE FALSE
>     > [2,] FALSE FALSE
>     > [3,] FALSE FALSE
>     > ## This is right
>
> Well, the two arrays are different:
> The first has a '2' instead of a '4'
> ((and this would not happen if you used 1:6  instead  ..))
>
>     > I'll wait a bit before filing a bug report so that any error I may be
>     > making can be pointed out (note that my R version is NOT current, so
> I need
>     > to update).
>
>     >> sessionInfo()
>     > R version 3.5.2 (2018-12-20)
>     > Platform: x86_64-apple-darwin15.6.0 (64-bit)
>     > Running under: macOS Mojave 10.14.4
>
>     > Matrix products: default
>     > BLAS:
>     >
> /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
>     > LAPACK:
>     >
> /Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRlapack.dylib
>
>     > locale:
>     > [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
>
>     > attached base packages:
>     > [1] stats     graphics  grDevices utils     datasets  methods   base
>
>     > loaded via a namespace (and not attached):
>     > [1] compiler_3.5.2 tools_3.5.2
>
>     > Bert Gunter
>
>     > "The trouble with having an open mind is that people keep coming
> along and
>     > sticking things into it."
>     > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>
>
>     > On Thu, May 9, 2019 at 8:10 AM Juan Gomez <juangomezduaso using gmail.com>
> wrote:
>
>     >> I think there is an error in duplicated() help page when it states
> that:
>     >> "The array method calculates for each element of the sub-array
>     >> specified by MARGIN if the remaining dimensions are identical to
> those
>     >> for an earlier (or later, when fromLast = TRUE) element (in
> row-major
>     >> order). "
>     >> Instead of:
>     >> "... (in column-major order)"
>     >>
>     >> For instance:
>     >> duplicated(array(c(1,2,3,2,5,6),c(3,2)), MARGIN=1:2)
>     >> [,1]  [,2]
>     >> [1,] FALSE  TRUE
>     >> [2,] FALSE FALSE
>     >> [3,] FALSE FALSE
>     >> >
>     >>
>     >> ______________________________________________
>     >> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>     >> https://stat.ethz.ch/mailman/listinfo/r-help
>     >> PLEASE do read the posting guide
>     >> http://www.R-project.org/posting-guide.html
>     >> and provide commented, minimal, self-contained, reproducible code.
>     >>
>
>     > [[alternative HTML version deleted]]
>
>     > ______________________________________________
>     > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>     > https://stat.ethz.ch/mailman/listinfo/r-help
>     > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
>     > and provide commented, minimal, self-contained, reproducible code.
>

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