>>>>> Gabriel Becker
>>>>> on Mon, 15 Jul 2019 13:29:28 -0700 writes:
> Hi Morgan,
> So if the goal is output identical to calling factor, one thing youc an
> do is construct and evaluate a call to the R-level factor function. That
> would work and be guaranteed to meet your requirement.
> The factor function is implemented with R code, without even any direct
> calls down to C code, so there isn't any C level functionality already
> there that you could try to hit directly.
> If you really really needed to write it using only C (and not hitting the
R
> evaluator), I suppose you could. You'd need to do the following, I think:
[... hoop jumping ...]
[... hoop jumping ...]
> Personally, unless there was a really compelling reason not to, I'd just
do
> the create and evaluate an R-level call thing instead.
I'm strongly supporting that. That's the only will not to have
to change your (potentially brittle) C code if factor() or
as.factor() .. is tweaked in a future version of R.
> On Mon, Jul 15, 2019 at 3:25 AM Morgan Morgan <morgan.email...@gmail.com>
> wrote:
>> Hi,
>>
>> Using the R C PAI, is there a way to convert to convert STRSXP or INTSXP
to
>> factor.
>>
>> The idea would be to do in C something similar to the "factor" function
>> (example below):
>>
>> > letters[1:5]
>> # [1] "a" "b" "c" "d" "e"
>>
>> > factor(letters[1:5])
>> # [1] a b c d e
>> # Levels: a b c d e
>>
>> There is the function setAttrib the levels of a SXP however when returned
>> to R the object is of type character not factor. Ideally what i would
like
>> to return from the C function is the same output as above when the input
is
>> of type character.
>>
>> Please let me if you need more informations.
>> Thank you
>> Best regards
>> Morgan
>>
>> [[alternative HTML version deleted]]
>>
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