Bill Dunlap
2022-Aug-09 19:10 UTC
[Rd] Should `as.difftime()` convert integer input to double?
Forcing difftime's payload to be numeric would avoid anomalies like> as.difftime(123456789L, units="secs") * 100LTime difference of NA secs Warning message: In e2 * unclass(e1) : NAs produced by integer overflow> as.difftime(123456789, units="secs") * 100LTime 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 at 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]] > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel >[[alternative HTML version deleted]]
Kurt Hornik
2022-Aug-14 16:34 UTC
[Rd] Should `as.difftime()` convert integer input to double?
>>>>> 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 at 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]] >> >> ______________________________________________ >> R-devel at r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel >>> [[alternative HTML version deleted]]> ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel