From: Brian Beckage <[EMAIL PROTECTED]> > > Thanks to all who responded to my posting. > > At 11:39 AM -0500 11/12/03, Gabor Grothendieck wrote: > >You are being hit by a timezone problem. Its not really shifting > >the days by one. Its working in the GMT timezone, not yours. > > > >If you can accept a date format that chron supports then this is the > >easiest solution since chron does not support timezones and so can't > >give you such problems in the first place. For example, > >the following stays in chron the whole time: > > > > format(datesTest, format="m/day/year") > > [1] "Oct/01/1952" "Oct/02/1952" "Oct/03/1952" > > > >If you must convert to POSIXt to take advantage of a format > >only supported by POSIXt then use POSIXlt and specify the timezone explictly: > > > > format(as.POSIXlt(datesTest,tz="GMT"), "%m/%d/%Y") > > [1] "10/01/1952" "10/02/1952" "10/03/1952" > > This solved the problem using as.POSIXlt(). I guess the tz argument > doesn't solve the problem using as.POSIXct(). In any case, I'm able > to use as.POSIXlt() in my current application.
You can use POSIXct but its a bit trickier. Assuming datesTest is a chron vector, as before you can do this. format(as.POSIXct(datesTest), "%m/%d/%Y", tz="GMT") # right Note that in this case you have to use the tz parameter on format, NOT on as.POSIXct: format(as.POSIXct(datesTest, tz="GMT"), "%m/%d/%Y") # wrong ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help