[R] error in duplicated() man page

[Martin Maechler]

>>>>> 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
    >> >
    >> 
    >> ______________________________________________
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    >> and provide commented, minimal, self-contained, reproducible code.
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    > ______________________________________________
    > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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    > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
    > and provide commented, minimal, self-contained, reproducible code.