On Aug 18, 2010, at 6:23 PM, Gabor Grothendieck wrote:
> No one answered this so I submitted it to the bugs system and there I
> got the response that it is documented behavior; however, whether its
> documented or not is hardly the point -- its undesirable that tzone is
> lost when using c.
>
That's one man's opinion - from docs
if you want to specify an object in a particular timezone but
to be printed in the current timezone you may want to remove the
‘"tzone"’ attribute (e.g. by ‘c(x)’).
so apparently that is a design choice and hence I doubt it can be changed as it
would break code that uses that feature. As many things in R whether it was a
good choice is up for debate but it has been made already. (Think about how you
would combine different times with different tzones - there is no "right" way
to do so and thus stripping is very plausible and consistent)
Cheers,
Simon
> On Thu, Aug 12, 2010 at 11:33 AM, Gabor Grothendieck
> <ggrothendi...@gmail.com> wrote:
>> Currently if x1 and x2 are POSIXct then c(x1, x2) will not have a
>> tzone attribute even if x1 or x2 or both do but it should.
>>
>> This could be fixed with the following c.POSIXct:
>>
>> c.POSIXct <- function (..., recursive = FALSE) {
>> tzones <- lapply(list(...), attr, which = "tzone")
>> lengths <- sapply(tzones, length)
>> if (any(lengths > 1)) stop("tzone cannot have length greater than 1")
>> which <- sapply(tzones, length) == 1
>> tzone <- unique(unlist(tzones[which]))
>> if (length(tzone) != 1) tzone <- NULL
>> structure(c(unlist(lapply(list(...), unclass))), class = c("POSIXt",
>> "POSIXct"), tzone = tzone)
>> }
>>
>> # test
>> x1 <- Sys.time()
>> x2 <- structure(x1, tzone = "UTC")
>> x3 <- structure(x1, tzone = "other")
>>
>> # these all currently give NULL but with
>> # above give indicated value
>>
>> attr(c(x1, x1), "tzone") # NULL
>> attr(c(x2, x2), "tzone") # "UTC"
>> attr(c(x1, x2), "tzone") # "UTC"
>> attr(c(x2, x1), "tzone") # "UTC"
>> attr(c(x1, x2, x3), "tzone") # NULL
>>
>
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