In the development version of R the output changes to: > x1 = as.POSIXlt("2008-01-02 00:58:00") > > x2 = as.POSIXct("2008-01-02 00:58:00") > > as.Date(x1); as.Date(x2) [1] "2008-01-02" [1] "2008-01-02" > > R.version.string [1] "R version 2.8.0 Under development (unstable) (2008-06-28 r46012)"
On Thu, Jul 3, 2008 at 6:48 PM, Angel Spassov <[EMAIL PROTECTED]> wrote: > Hi, > > I'm working with objects of classes "Date","POSIXlt" and "POSIXct" and still > having some Date/Time-related concepts unclear. In the documentation of > "as.Date" one can find: > > "The 'as.Date' methods accept ... '"POSIXlt"' and '"POSIXct"'. (The last are > converted to days by ignoring the time after midnight in the representation > of the time in UTC.)" > > > As far as why "POSIXct" ignores the time after midnight is still open > question for me and some basic hints about why this happens would be greatly > appreciated? Having mentioned this one can avoid an eventual confusion when > interpreting the following: > > > x1 = as.POSIXlt("2008-01-02 00:58:00") > > x2 = as.POSIXct("2008-01-02 00:58:00") > > as.Date(x1); as.Date(x2) > > [1] "2008-01-02" > > [1] "2008-01-01" > > > which happened to me at the beginning. Aside from this, my real problem was > with the (very) unexpected behavior of the 'as.data.frame'-function which > seems to coerce the class '"POSIXlt"' to class '"POSIXct"' and consequently > making my life considerably harder through: > > as.Date(as.data.frame(x1)[1,1]) > > [1] "2008-01-01" > > where > > as.Date(x1) > > [1] "2008-01-02" > > > Can anyone offer me a strong evidence that exactly this behaviour of R gives > me advantage over the "naturally" expected conversion to "2008-01-02"? > Thanks in advance. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > 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. > ______________________________________________ R-help@r-project.org mailing list 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.