Would it make sense for as.Date.POSIXct to not assume tz="UTC" if the POSIXct object has a valid tzone attribute? Current behavior may be confusing in certain cases, for example:
(d <- structure(1090450800, tzone="Europe/Berlin",
+ class=c("POSIXct","POSIXt")))
[1] "2004-07-22 01:00:00 CEST"
as.Date(d)
[1] "2004-07-21"
as.Date(as.POSIXlt(d))
[1] "2004-07-22"
as.Date(d, tz=attr(d,'tzone'))
[1] "2004-07-22" Best, -- Joshua Ulrich | about.me/joshuaulrich FOSS Trading | www.fosstrading.com R/Finance 2013: Applied Finance with R | www.RinFinance.com