[Rd] Should `as.difftime()` convert integer input to double?

[Kurt Hornik]

>>>>> Davis Vaughan writes:

> Kurt,
> Thanks so much! Do you think `as.difftime()` should retain names? With your
> patch, I don't *think* this will retain names anymore:

> # This is the released behavior
> names(as.difftime(c(x=1), units = "secs"))
> #> [1] "x"

Thanks.  Changed now with c82723.

Best
-k

> -Davis

> On Sun, Aug 14, 2022 at 12:34 PM Kurt Hornik <Kurt.Hornik using wu.ac.at> wrote:

>> >>>>> Bill Dunlap writes:
>> 
>> Thanks: fixed now in the trunk with c82716.
>> 
>> Best
>> -k
>> 
>> > Forcing difftime's payload to be numeric would avoid anomalies like
>> >> as.difftime(123456789L, units="secs") * 100L
>> > Time difference of NA secs
>> > Warning message:
>> > In e2 * unclass(e1) : NAs produced by integer overflow
>> >> as.difftime(123456789, units="secs") * 100L
>> > Time difference of 12345678900 secs
>> 
>> > Note that there are packages (e.g., fst, a serialization package) which
>> can
>> > (in C++ code) understand and create difftimes with integer payloads, so
>> you
>> > may have trouble completely getting rid of such things.
>> 
>> > -Bill
>> 
>> > On Tue, Aug 9, 2022 at 11:26 AM Davis Vaughan <davis using rstudio.com> wrote:
>> 
>> >> Hi all,
>> >>
>> >> Currently, `as.difftime()` with an integer input will produce a difftime
>> >> object that internally is built on an integer vector, i.e.:
>> >>
>> >> x <- as.difftime(1L, units = "secs")
>> >> typeof(x)
>> >> #> [1] "integer"
>> >>
>> >> x <- as.difftime(1, units = "secs")
>> >> typeof(x)
>> >> #> [1] "double"
>> >>
>> >> I feel like difftime objects should always be built on *double* vectors.
>> >> There are a few reasons I feel like this should be true:
>> >>
>> >> - There is an `as.double.difftime()` method, but no
>> `as.integer.difftime()`
>> >> method, which implies something about what the underlying storage type
>> is
>> >> assumed to be.
>> >>
>> >> - AFAIK, there is no other way to produce a difftime object with integer
>> >> storage using the exposed API (aside from abusing the internal
>> .difftime()
>> >> helper). Even `.Date(1L) - .Date(1L)` produces a difftime with double
>> >> storage.
>> >>
>> >> - `seq.Date()` used to be able to produce dates with integer storage,
>> but
>> >> as of recently even that edge case has been altered to always produce
>> dates
>> >> with double storage. So a change to also force difftime to have double
>> >> storage would feel consistent with that.
>> >>
>> >>
>> https://github.com/wch/r-source/commit/0762ee983813c4df9b93f6b5ee52c910dcd3ab39
>> >>
>> >> It looks like a patch to `as.difftime()` would be fairly straightforward
>> >> (i.e. ensuring that integer input is coerced to double), so I'd be
>> happy to
>> >> attempt one if someone else agrees that this should be changed.
>> >>
>> >> Thanks,
>> >> Davis
>> >>
>> >> [[alternative HTML version deleted]]
>> >>
>> >> ______________________________________________
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>> >>
>> 
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>> 
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