[R] Match ISO 8601 week-of-year numbers to month-of-year numbers on Windows with German locale

[Bob Rudis]

Aye, but this:

  some_dates <- as.POSIXct(c("2015-12-24", "2015-12-31", "2016-01-01",
"2016-01-08"))

  (year_week <- format(some_dates, "%Y-%U"))
  ## [1] "2015-51" "2015-52" "2016-00" "2016-01"

  (year_week_day <- sprintf("%s-1", year_week))
  ## [1] "2015-51-1" "2015-52-1" "2016-00-1" "2016-01-1"

  (as.POSIXct(year_week_day, format = "%Y-%U-%u"))
  ## [1] "2015-12-21 EST" "2015-12-28 EST" "2016-01-04 EST" "2016-01-04 EST"

works fine on macOS & Linux (Ubuntu, anyway), but it fails on Windows
(10, 64bit, R 3.3.2):

  (as.POSIXct(year_week_day, format = "%Y-%U-%u"))
  ## [1] "2015-12-21 PST" "2015-12-28 PST" NA               "2016-01-04 PST"

On 1/12/17, David Winsemius <dwinsemius at comcast.net> wrote:
>
>> On Jan 12, 2017, at 8:14 AM, Janko Thyson <janko.thyson at gmail.com> wrote:
>>
>> Dear list,
>>
>> I'm experiencing problems with converting strings of the format
>> "YYYY-<weekofyear>" (e.g. 2016-01, 2016-52) to proper POSIX dates which
>> (I
>> think) I need in order to retrieve the month-of-the-year number.
>>
>> Simpler put: I'd like to match week-of-the-year numbers to
>> month-of-the-year numbers. Ideally, the week-of-the-year number would
>> follow the ISO 8601 convention (i.e. format argument "%V") instead of the
>> US (format argument "%U") or UK (format argument "%W") convention.
>>
>> After posting this to Stackoverflow, I have strong reasons to believe
>> that
>> the issue is caused by Windows:
>> http://stackoverflow.com/questions/41616407/match-iso-8601-week-numbers-to-month-of-year-on-windows-with-german-locale/41617215?noredirect=1#comment70436768_41617215
>>
>> Example:
>>
>> # ISO 8601 convention:
>>
>> (yw <- format(posix, "%Y-%V"))
>
> The documentation for R datetime format parameters ?strptime says %V is
> ignored on input.
>
>
>> # [1] "2015-52" "2015-53" "2016-53" "2016-01"
>> ywd <- sprintf("%s-1", yw)(as.POSIXct(ywd, format = "%Y-%V-%u"))
>
> The documentation for R datetime format parameters ( = ?strptime) says %V is
> ignored on input.
>
> You should leartn to post plain text to r-help.
>
> --
> David.
>
>
>> # [1]
>> "2015-01-12 CET" "2015-01-12 CET" "2016-01-12 CET" "2016-01-12 CET"#
>> -> utterly wrong!!!
>>
>> # US convention:
>> (yw <- format(posix, "%Y-%U"))# [1] "2015-51" "2015-52" "2016-00"
>> "2016-01"
>> ywd <- sprintf("%s-1", yw)(as.POSIXct(ywd, format = "%Y-%U-%u"))# [1]
>> "2015-12-21 CET" "2015-12-28 CET" NA               "2016-01-04 CET"#
>> -> NA problem for week 00A fellow R user tested this on both macOS and
>> Ubuntu and he didn't encounter the issue:
>>
>> some_dates <- as.POSIXct(c("2015-12-24", "2015-12-31", "2016-01-01",
>> "2016-01-08"))
>> (year_week <- format(some_dates, "%Y %U"))## [1] "2015 51" "2015 52"
>> "2016 00" "2016 01"
>> (year_week_day <- sprintf("%s 1", year_week))## [1] "2015 51 1" "2015
>> 52 1" "2016 00 1" "2016 01 1"
>> (as.POSIXct(year_week_day, format = "%Y %U %u"))## [1] "2015-12-21
>> EST" "2015-12-28 EST" "2016-01-04 EST" "2016-01-04 EST"
>>
>> My session info:
>>
>>> sessionInfo()
>> R version 3.3.2 (2016-10-31)
>> Platform: x86_64-w64-mingw32/x64 (64-bit)
>> Running under: Windows >= 8 x64 (build 9200)
>>
>> locale:[1] LC_COLLATE=German_Germany.1252
>> LC_CTYPE=German_Germany.1252       LC_MONETARY=German_Germany.1252
>> [4] LC_NUMERIC=C                       LC_TIME=English_United
>> States.1252
>>
>> attached base packages:[1] stats     graphics  grDevices utils
>> datasets  methods   base
>>
>> other attached packages:
>> [1] fva_0.1.0       digest_0.6.10   readxl_0.1.1    dplyr_0.5.0
>> plyr_1.8.4      magrittr_1.5
>> [7] memoise_1.0.0   testthat_1.0.2  roxygen2_5.0.1  devtools_1.12.0
>>
>> loaded via a namespace (and not attached):
>> [1] Rcpp_0.12.8     lubridate_1.6.0 assertthat_0.1  packrat_0.4.8-1
>> crayon_1.3.2    withr_1.0.2
>> [7] R6_2.2.0        DBI_0.5-1       stringi_1.1.2   rstudioapi_0.6
>> tools_3.3.2     stringr_1.1.0  [13] tibble_1.2
>>
>> Any idea on how to workaround this issue on Windows?
>>
>> Thanks and best regards,
>>
>> Janko Thyson
>>
>> 	[[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> David Winsemius
> Alameda, CA, USA
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>