[Rd] stringsAsFactors and type.convert()

[Arni Magnusson]

Dear Martin,

Thank you for the well-reasoned response. I realized I was rather late to make this suggestion for 4.0.0, changing a somewhat low-level function that can indeed affect packages.

I was just reviewing some R user scripts that were using type.convert(), mainly on data frames. In all cases, people were passing as.is=TRUE, so I was reminded that I would not be the only user who would appreciate if as.is=TRUE becomes the default at some point.

So I am happy to hear that the help page now mentions that the as.is=TRUE is planned to be the default at some point in the future. Looking forward to the 4.0.0 official release - all positive changes!

All the best,
Arni

________________________________
From: Martin Maechler <maechler using stat.math.ethz.ch>
Sent: Monday, April 20, 2020 6:23:31 PM
To: Arni Magnusson
Cc: r-devel using r-project.org
Subject: Re: [Rd] stringsAsFactors and type.convert()

>>>>> Arni Magnusson
>>>>>     on Mon, 13 Apr 2020 22:20:19 +0000 writes:

    > If read.table() is defaulting to "character" instead of "factor" data type, shouldn't type.convert() also default to "character" in R 4.0.0?
    > This would seem like a good time to change the default to type.convert(as.is=TRUE), to align it with the new default in read.table and data.frame. I think many R >=4.0.0 users would be happy with as.is=TRUE as the default in type.convert.

    > I'm happy to work on the patch and run tests if that is helpful.

    > Cheers,
    > Arni

Dear Arni,
thank you for the notice, which unfortunately wasn't noticed
(Easter break etc) and was too late in any case to fulfill the
criterion of a small trivial bug fix  for  R 4.0.0 beta (very close
to becoming RC (= "Release Candidate").

Even when type.convert() may not be used much directly (but
rather indirectly via read.table() where there's no problem), we
found it too risky to destabilize the R 4.0.0 prereleases.
As you all know there were ( / are?) still package changes
needed and a few other important "todo"s, so we had to decide to
postpone this (even for R-devel) to after releasing R 4.0.0
coming Friday.

I've committed a change to the help page which does mention that
the default for 'as.is' is planned to be changed.

Also, the help page's  "Details" section, for a long time has
ended with

     Since this is a helper function, the caller should always pass an
     appropriate value of 'as.is'.

If useRs and package authors have followed this advice, they
won't be bitten at all.

Best regards,
Martin