David.
>
> Thanks for help,
> Janko
>
> On Thu, Jan 12, 2017 at 8:37 PM, 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]]
>>>
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>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> David Winsemius
>> Alameda, CA, USA
>>
David Winsemius
Alameda, CA, USA