Your POSIXct comment is what I have experienced as well. It works fine in keys as long as there are no fractional seconds, but in the fractional-seconds case an error (quite sure...) is given.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Matthew Dowle Sent: Thursday, March 08, 2012 11:44 AM To: Chris Neff Cc: [email protected] Subject: Re: [datatable-help] problems with adding a DateTime column Ah, we crossed emails. It's been reported (to me offlist) that POSIXct may be working in keys, in integer form without any fractional seconds I guess. Worth a try. > Try as.IDate around your strptime. strptime returns POSIXlt which > isn't really amenable to data tables (or frames for that matter). In > base R you would usually convert to POSIXct, but IDate is integer > based and made to be able to key on dates in data.tables. > > On Thu, Mar 8, 2012 at 11:11 AM, Alexander Peterhansl > <[email protected]> wrote: >> Dear Datatable-Help: >> >> I'm running R version 2.14.1 and data.table 1.7.10 (on Windows 7 and >> Linux). On both systems I get a strange result in the following toy >> example: >> >> >> >> test <- data.table(A=c(1,2,3)) >> >> test[,B:= c("2011-01-01","2011-01-02","2011-01-03")] >> >> test[,C:= >> strptime(c("2011-01-01","2011-01-02","2011-01-03"),format="%Y-%m-%d") >> ] >> >> Output: >> >> A B C >> >> [1,] 1 2011-01-01 0, 0, 0 >> >> [2,] 2 2011-01-02 0, 0, 0 >> >> [3,] 3 2011-01-03 0, 0, 0 >> >> >> >> Columns A and B show the expected behavior. Column C was supposed to >> simply convert the date strings into DateTime types. Clearly this is >> not happening. >> >> >> >> Please help. >> >> Regards, >> >> Alex >> >> >> >> >> >> >> _______________________________________________ >> datatable-help mailing list >> [email protected] >> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatabl >> e-help > _______________________________________________ > datatable-help mailing list > [email protected] > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable > -help > _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
