Hello,
Thank you both, Duncan and Martin, for the quick and clear answer.
I hadn't considered printing `[.data.frame`, which is in fact very
useful, but I had read the Arguments section. What I didn't realize was
that it was the answer to the question. Sorry for the noise.
Rui Barradas
Às 13:51 de 29/12/20, Martin Maechler escreveu:
Duncan Murdoch
on Tue, 29 Dec 2020 08:37:51 -0500 writes:
> On 29/12/2020 8:29 a.m., Rui Barradas wrote:
>> Hello,
>>
>> R 4.0.3 on Ubuntu 20.10, session info at end.
>>
>> Isn't the default value of argument drop missing in
>>
>> ?`[.data.frame`
>>
>> Usage:
>>
>> ## S3 method for class 'data.frame'
>> x[i, j, drop = ]
>>
>>
>> I had the impression that it was TRUE (it is when running the function,
>> I'm talking about the docs).
> No, you can see it if you print `[.data.frame`:
>> `[.data.frame`
> function (x, i, j, drop = if (missing(i)) TRUE else length(cols) ==
> 1)
> So if you ask for specific rows and your dataframe has more than one
> column, it defaults to FALSE.
> I think the Rd checks allow you to leave out defaults, but don't allow
> you to state them incorrectly, so that's probably why it is left as
> blank in the Usage section, and explained in the Arguments section.
> Duncan Murdoch
Yes, indeed, Duncan, it is as you think (above).
It is "official" in the sense that we've used this for a long
time in order to keep the 'Usage' section cleaner, when some
defaults are sophisticated, and a help page reader should rather
read the corresponding argument description.
Martin
>> sessionInfo()
>> R version 4.0.3 (2020-10-10)
>> Platform: x86_64-pc-linux-gnu (64-bit)
>> Running under: Ubuntu 20.04.1 LTS
>>
>> Matrix products: default
>> BLAS: /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.9.0
>> LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.9.0
>>
>> locale:
>> [1] LC_CTYPE=pt_PT.UTF-8 LC_NUMERIC=C
>> [3] LC_TIME=pt_PT.UTF-8 LC_COLLATE=pt_PT.UTF-8
>> [5] LC_MONETARY=pt_PT.UTF-8 LC_MESSAGES=pt_PT.UTF-8
>> [7] LC_PAPER=pt_PT.UTF-8 LC_NAME=C
>> [9] LC_ADDRESS=C LC_TELEPHONE=C
>> [11] LC_MEASUREMENT=pt_PT.UTF-8 LC_IDENTIFICATION=C
>>
>> attached base packages:
>> [1] stats graphics grDevices utils datasets methods base
>>
>> loaded via a namespace (and not attached):
>> [1] compiler_4.0.3 tools_4.0.3
>>
>>
>> Happy holidays,
>>
>> Rui Barradas
>>
>> ______________________________________________
>> R-devel@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
> ______________________________________________
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> https://stat.ethz.ch/mailman/listinfo/r-devel
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