I'm using as.POSIXct to parse times with timezones, like this:
as.POSIXct("2009-01-05 14:19 +1200", format="%Y-%m-%d %H:%M %z")
However, if the string includes the timezone information +1300, the function returns NA:
> as.POSIXct("2009-01-05 14:19 +1300", format="%Y-%m-%d %H:%M %z")
Aparently +1300 is a valid timezone (NZDT – New Zealand Daylight Time).
(previously reported at http://stackoverflow.com/questions/23182569/as-posixct-rejects-1300-timezone)
+1300 is not a timezone: it is an offset (see the description of %z in ?strptime). And the issue is not as.POSIXct but strptime: it was the third-party code use by strptime which does not recognize that offset.