[datatable-help] Unable to find difference between two IDates

[Short, Tom]

Harish, I just checked in another attempt at fixing this bug. One side effect this pointed out is a difference in the way I decided to handle as.POSIXct for IDate's. Please note the following difference:

> as.POSIXct( as.Date( "2010-01-01" ))
[1] "2009-12-31 19:00:00 EST"
> as.POSIXct( as.IDate( "2010-01-01" ))
[1] "2010-01-01 UTC"

And also:

> as.POSIXct( as.Date( "2010-01-01" ), tz = "EST5EDT")
[1] "2009-12-31 19:00:00 EST"
> as.POSIXct( as.IDate( "2010-01-01" ), tz = "EST5EDT")
[1] "2010-01-01 EST"

I try to keep IDate's as roundable to dates and revert to UTC (instead of the local time zone) if the time zone isn't specified.


- Tom


 

> -----Original Message-----
> From: Harish [mailto:harishv_99 at yahoo.com] 
> Sent: Tuesday, June 29, 2010 19:42
> To: Short, Tom
> Subject: RE: [datatable-help] Unable to find difference 
> between two IDates
> 
> Tom,
> 
> I am afraid I still have the same issue...  I just downloaded 
> the latest version from R-Forge (Rev 100).  Your fix was in 
> Rev 99 I believe.
> 
> > install.packages("data.table", repos="http://R-Forge.R-project.org")
> Warning in install.packages("data.table", repos = 
> "http://R-Forge.R-project.org") :
>   argument 'lib' is missing: using 'C:\Documents and 
> Settings\User\My Documents/R/win-library/2.11'
> trying URL 
> 'http://R-Forge.R-project.org/bin/windows/contrib/2.11/data.ta
ble_1.5.zip'
> Content type 'application/zip' length 654684 bytes (639 Kb) 
> opened URL downloaded 639 Kb
> 
> package 'data.table' successfully unpacked and MD5 sums checked
> 
> The downloaded packages are in
>         C:\Documents and Settings\User\Local 
> Settings\Temp\RtmpjXn6zO\downloaded_packages
> > library(data.table)
> > a <- as.IDate( "2010-06-26" )
> > b <- as.IDate( "2010-06-23" )
> > a
> [1] "2010-06-26"
> > b
> [1] "2010-06-23"
> > a-b
> Time difference of NA days
> 
> 
> Harish
> 
> 
> --- On Mon, 6/28/10, Short, Tom <TShort at epri.com> wrote:
> 
> > From: Short, Tom <TShort at epri.com>
> > Subject: RE: [	] Unable to find difference between two 
> > IDates
> > To: "Harish" <harishv_99 at yahoo.com>, 
> > datatable-help at lists.r-forge.r-project.org
> > Date: Monday, June 28, 2010, 6:09 AM
> > Harish, I just committed a fix to
> > R-forge that should fix this bug.
> > 
> > - Tom
> >  
> > 
> > > -----Original Message-----
> > > From: datatable-help-bounces at lists.r-forge.r-project.org
> > 
> > > [mailto:datatable-help-bounces at lists.r-forge.r-project.org]
> > 
> > > On Behalf Of Harish
> > > Sent: Sunday, June 27, 2010 01:38
> > > To: datatable-help at lists.r-forge.r-project.org
> > > Subject: [datatable-help] Unable to find difference
> > between two IDates
> > > 
> > > I am unable to find the difference between two IDate
> > objects. 
> > >  The way I can get around it is to use
> > Date.  Am I doing
> > > something wrong here?
> > > 
> > > ============
> > > 
> > > a <- as.IDate( "2010-06-26" )
> > > b <- as.IDate( "2010-06-23" )
> > > a - b # Erroneously get "Time difference of NA days"
> > > as.Date( a ) - as.Date( b ) # Correctly get 3 days
> > > 
> > > ============
> > > 
> > > 
> > > Regards,
> > > Harish
> > > 
> > > 
> > > 
> > >       
> > > _______________________________________________
> > > datatable-help mailing list
> > > datatable-help at lists.r-forge.r-project.org
> > > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/d
> > atatable-help
> > > 
> > 
> 
> 
>       
>