Hello, Yes this seems to be a bug introduced sometime towards the end of the development cycle towards 1.9.x. Thanks for reporting. Will try to fix asap.
The problem is that `by=` doesn't retain the class. If you do: `dt[, print(d), by=list(id, d)]` you'll see that. For now, I guess you'll have to explicitly convert it back to POSIX/Date class and do your operations in `j`, until a commit with the fix is rolled out. Arun From: dnlbrky [email protected] Reply: dnlbrky [email protected] Date: March 24, 2014 at 6:36:41 AM To: [email protected] [email protected] Subject: [datatable-help] "Error in Ops.POSIXt" using 1.9.x Running the following using data.table version 1.8.10 or 1.8.11 (Windows 7) works as expected: n <- 12 dt <- data.table(id=rep(letters[1:(n/3)], each=3), d=seq(as.POSIXct("2013-01-01"), by="month", length.out=n)) dt[, list(d2=seq(d, dt[, max(d)], by="month")), by=list(id, d)][1:15] > id d d2 > 1: a 2013-01-01 2013-01-01 > 2: a 2013-01-01 2013-02-01 > 3: a 2013-01-01 2013-03-01 > 4: a 2013-01-01 2013-04-01 > 5: a 2013-01-01 2013-05-01 > 6: a 2013-01-01 2013-06-01 > 7: a 2013-01-01 2013-07-01 > 8: a 2013-01-01 2013-08-01 > 9: a 2013-01-01 2013-09-01 > 10: a 2013-01-01 2013-10-01 > 11: a 2013-01-01 2013-11-01 > 12: a 2013-01-01 2013-12-01 > 13: a 2013-02-01 2013-02-01 > 14: a 2013-02-01 2013-03-01 > 15: a 2013-02-01 2013-04-01 After upgrading to 1.9.x (latest version at writing was 1.9.3) however, I get the following: >Error in Ops.POSIXt(del, by) : '/' not defined for "POSIXt" objects If I replace `seq` with `seq.Date` then I get: >Error in seq.Date(d, dt[, max(d)], by = "month") : 'from' must be a "Date" object Am I doing something wrong? Is this a bug? Is there a workaround? -- View this message in context: http://r.789695.n4.nabble.com/Error-in-Ops-POSIXt-using-1-9-x-tp4687400.html Sent from the datatable-help mailing list archive at Nabble.com. _______________________________________________ datatable-help mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
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