Posted here https://github.com/Rdatatable/datatable/issues/688
However, I couldn't tag it as a bug (didn't find the option to add a label, sorry!) On Mon, Jun 9, 2014 at 6:29 PM, Arunkumar Srinivasan <[email protected]> wrote: > Juan, > > On how to report a bug: > 1) Go to https://github.com and create an account, if you don't already have > one. > 2) Go to our project page, while signed in: > https://github.com/Rdatatable/datatable > 3) Click "Issues" on the right side of the page. > 4) This issue doesn't already exist. So, hit "New issue" (green button on > the right). > 5) Provide a title. Fill the body - remember you can format code using > Markdown (as well as Github flavoured markdown). For example, to write > R-code, you can do: > > ```S > your R-code > ``` > > The S is the lexer type (for highlighting code using Github flavoured > markdown). > 6) Add a label (equivalent of tag or tracker type in R-Forge) by clicking on > "bug" on the right side. > 7) Preview your post, if you want to. Then click "Submit new issue". > > --- > > On the bug itself: This is because `reshape2:::dcast` doesn't preserve > attributes. And we wanted to be consistent with their result at the time of > writing. > However, since that time, `reshape2` has obtained newer implementation of > "melt", written by Kevin Ushey, where attributes are preserved as long as > all the columns that you're asking for to be "molten" are of the same type. > But this doesn't happen for "factors" by default because that might break > existing code - and therefore obtained a new argument "factorsAsStrings", > IIUC. I personally find these things adding a layer of complexity. But > that's the case with "melt". > > It's really hard to tell from reshape2's ?melt or ?cast what's the case > regarding attributes. But my guess is that we should, starting with your > post, try to define what's what and document it instead of relying entirely > on being consistent with reshape2's behaviour, as we do already differ from > reshape2 already slightly. > > We're very much younger than reshape2's melt/cast. So, I think we might be > able to rectify these things on consistency and rules relatively easier. > > Arun > > From: Juan Manuel Truppia [email protected] > Reply: Juan Manuel Truppia [email protected] > Date: June 9, 2014 at 10:13:05 PM > To: [email protected] > [email protected] > Subject: [datatable-help] dcast.data.table loses column classes when column > is date > > Here is a reproducible example > > dcast.data.table(data = data.table(id = c(1,1,2,2), ty = > c("a","b","a","b"), da = Sys.Date()), formula = id ~ ty) > > I don't know how to report a bug, if someone guides me, I'll be much obliged > > Thanks! > _______________________________________________ > 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
