This is intentional: why did you send a bug report? Please read the
section on BUGS in the FAQ and tell us how this contradicts the
documentation.
If you want a particular output format, you need to specify it:
x <- strptime("10/5/2004 00:00:00 CDT", "%m/%d/%Y %H:%M:%S
%Z")
format(x, "%Y-%m-%d %H:%M:%S")
[1] "2004-10-05 00:00:00"
but print() is allowed to suppress 0's. Did you bother to read the code:
> format.POSIXlt
function (x, format = "", usetz = FALSE, ...)
{
if (!inherits(x, "POSIXlt"))
stop("wrong class")
if (format == "") {
times <- unlist(unclass(x)[1:3])
format <- if (all(times[!is.na(times)] == 0))
"%Y-%m-%d"
else "%Y-%m-%d %H:%M:%S"
}
.Internal(format.POSIXlt(x, format, usetz))
}
?
On Thu, 28 Oct 2004 mcintosh@research.telcordia.com wrote:
> Full_Name: Allen McIntosh
> Version: 2.0.0
> OS: RedHat 9.0
> Submission from: (NULL) (67.80.175.118)
>
>
> The POSIX time printing routine gives strange results when asked to print a
time
> that is exactly midnight:
>
> TZ=CST6CDT R -q --no-save
> > strptime("10/5/2004 00:00:01 CDT", "%m/%d/%Y %H:%M:%S
%Z")
> [1] "2004-10-05 00:00:01"
> > strptime("10/5/2004 00:00:00 CDT", "%m/%d/%Y %H:%M:%S
%Z")
> [1] "2004-10-05"
> > strptime("10/4/2004 24:00:00 CDT", "%m/%d/%Y %H:%M:%S
%Z")
> [1] NA
>
> The first time is OK. The second is missing the HH:MM:SS.
> I'm OK with the last one being NA,
We don't need your permission: this is as documented.
> just did it to see if that was the way that
> the code wanted midnight.
>
> Get the underlying # seconds:
>
> > zz <- as.POSIXct(strptime("10/5/2004 00:00:00 CDT",
"%m/%d/%Y %H:%M:%S %Z"))
> > attr(zz,"class") <- NULL
> > zz
> [1] 1096952400
> attr(,"tzone")
> [1] ""
> >
>
> and (just to see if the problem is glibc or something):
> $ cat ct.c
> #include <time.h>
> #include <stdio.h>
> main() {
> time_t z = 1096952400;
> printf("%s\n", ctime(&z));
> return 0;
> }
> $ gcc -o ct ct.c
> $ TZ=CST6CDT ./ct
> Tue Oct 5 00:00:00 2004
What has ctime() to do with this?
> This problem also observed with R 1.6.0 and R 1.8.1 (RedHat 7.3)
> The timezone doesn't seem to matter - this is just the first date that
tripped
> over this problem.
--
Brian D. Ripley, ripley@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595