[Tagged] Re: Question about Date Object and time zones
... or a timezone string. ... or do what I usually do and use POSIXct for dates as well as times, self-managing use of midnight local time for "dates".
On September 25, 2024 5:40:37 AM EDT, Ivan Krylov via R-help <r-help at r-project.org> wrote:
24 ???????? 2024 ?. 17:10:13 GMT+03:00, Luca Brinkmann via R-help <r-help at r-project.org> ?????:
My current understanding is, that a Date object does only save the days from the origin and no more information about timezones or other information (please correct me if I am wrong).
You are correct.
the date object is displayed in my RStudio environment as "2024-11-11 UTC".
This looks like a result of as.POSIXlt(<Date object>).
In contrast, getting the timezone information with base::format will yield the timezone information
base::format(d, format="%Z")
[1] "UTC"
That's an implementation detail: the format() method for Date objects conjures a temporary POSIXlt object and formats the result, and POSIXlt objects can contain time zone information.
Is there any way to add timezone information to an Date object (other than UTC) and keeping it a Date object?
Not with a plain 'Date'. What should a date in a timezone mean? Start of day? End of day? The whole 24-hour interval (except when it lasts 23 or 25 hours due to DST)? Perhaps you could store one (or two for an interval) POSIXt object(s) if you need timezone information for your dates.
Sent from my phone. Please excuse my brevity.