<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><p>Juan,</p><p><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">On how to report a bug:</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">1) Go to https://github.com and create an account, if you don't already have one.</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">2) Go to our project page, while signed in: <a href="https://github.com/Rdatatable/datatable">https://github.com/Rdatatable/datatable</a></div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">3) Click "Issues" on the right side of the page.</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">4) This issue doesn't already exist. So, hit "New issue" (green button on the right).</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">5) Provide a title. Fill the body - remember you can format code using <a href="https://help.github.com/articles/markdown-basics">Markdown</a> (as well as <a href="https://help.github.com/articles/writing-on-github">Github flavoured markdown</a>). For example, to write R-code, you can do:</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; "><br></div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">```S</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">your R-code</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">```</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; "><br></div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">The S is the lexer type (for highlighting code using Github flavoured markdown).</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">6) Add a label (equivalent of tag or tracker type in R-Forge) by clicking on "bug" on the right side. </div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">7) Preview your post, if you want to. Then click "Submit new issue".</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; "><br></div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">---</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; "><br></div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">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. </div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">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". </div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; "><br></div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">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.</div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; "><br></div><div id="bloop_customfont" style="font-family: Helvetica, Arial; background-color: rgb(255, 255, 255); margin: 0px; ">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.</div></p> <div id="bloop_sign_1402348474013064960" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">Arun</div></div> <div style="color:black"><br>From: <span style="color:black">Juan Manuel Truppia</span> <a href="mailto:jmtruppia@gmail.com">jmtruppia@gmail.com</a><br>Reply: <span style="color:black">Juan Manuel Truppia</span> <a href="mailto:jmtruppia@gmail.com">jmtruppia@gmail.com</a><br>Date: <span style="color:black">June 9, 2014 at 10:13:05 PM</span><br>To: <span style="color:black">datatable-help@lists.r-forge.r-project.org</span> <a href="mailto:datatable-help@lists.r-forge.r-project.org">datatable-help@lists.r-forge.r-project.org</a><br>Subject: <span style="color:black"> [datatable-help] dcast.data.table loses column classes when column is date <br></span></div><br> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>Here is a reproducible example
<br>
<br>dcast.data.table(data = data.table(id = c(1,1,2,2), ty =
<br>c("a","b","a","b"), da = Sys.Date()), formula = id ~ ty)
<br>
<br>I don't know how to report a bug, if someone guides me, I'll be much obliged
<br>
<br>Thanks!
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<br></div></div></span></blockquote><p></p><style>body{font-family:Helvetica,Arial;font-size:13px}</style><style>body {
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