<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><p>Hi Gabor,</p>
<p>Thanks for the quick response. Just to be clear, you don’t have to set <code>use.names=TRUE</code> when <code>fill=TRUE</code>. If you just set <code>fill=TRUE</code> and <code>use.names</code> happens to be <code>FALSE</code>, then it’ll automatically set it to <code>TRUE</code> (with a message/warning), which you can safely ignore. Do you find this still ugly? You’ll get the warning if you use <code>rbindlist</code> with just fill=TRUE (because use.name=FALSE by default).</p>
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.error { color:#AA0000; }</style></p><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div> <div id="bloop_sign_1400616300182107904" 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">Gabor Grothendieck</span> <a href="mailto:ggrothendieck@gmail.com">ggrothendieck@gmail.com</a><br>Reply: <span style="color:black">Gabor Grothendieck</span> <a href="mailto:ggrothendieck@gmail.com">ggrothendieck@gmail.com</a><br>Date: <span style="color:black">May 20, 2014 at 10:04:21 PM</span><br>To: <span style="color:black">Arunkumar Srinivasan</span> <a href="mailto:aragorn168b@gmail.com">aragorn168b@gmail.com</a><br>Cc: <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"> Re: [datatable-help] FR #5249 - rbindlist gains use.names and fill arguments <br></span></div><br> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>The requirement to set use.names to TRUE if fill is TRUE seems ugly.
<br>I suggest that fill be the default for use.names.
<br>
<br>On Tue, May 20, 2014 at 3:27 PM, Arunkumar Srinivasan
<br><aragorn168b@gmail.com> wrote:
<br>> Hello everyone,
<br>>
<br>> With the latest commit #1266, the extra functionality offered via rbind
<br>> (use.names and fill) is also now available to rbindlist. In addition, the
<br>> implementation is completely moved to C, and is therefore tremendously fast,
<br>> especially for cases where one has to bind using with use.names=TRUE and/or
<br>> with fill=TRUE. I’ll try to put out a benchmark comparing speed differences
<br>> with the older implementation ASAP.
<br>>
<br>> Note that this change comes with a very low cost to the default speed to
<br>> rbindlist - with use.names=FALSE and fill=FALSE. As an example, binding
<br>> 10,000 data.tables with 20 columns each, resulted in the new version running
<br>> in 0.107 seconds, where as the older version ran in 0.095 seconds.
<br>>
<br>> In addition the documentation for ?rbindlist also has been improved (#5158
<br>> from Alexander). Here’s the change log from NEWS:
<br>>
<br>> o 'rbindlist' gains 'use.names' and 'fill' arguments and is now
<br>> implemented entirely in C. Closes #5249
<br>> -> use.names by default is FALSE for backwards compatibility
<br>> (doesn't bind by names by default)
<br>> -> rbind(...) now just calls rbindlist() internally, except that
<br>> 'use.names' is TRUE by default,
<br>> for compatibility with base (and backwards compatibility).
<br>> -> fill by default is FALSE. If fill is TRUE, use.names has to be
<br>> TRUE.
<br>> -> At least one item of the input list has to have non-null column
<br>> names.
<br>> -> Duplicate columns are bound in the order of occurrence, like
<br>> base.
<br>> -> Attributes that might exist in individual items would be lost in
<br>> the bound result.
<br>> -> Columns are coerced to the highest SEXPTYPE, if they are
<br>> different, if/when possible.
<br>> -> And incredibly fast ;).
<br>> -> Documentation updated in much detail. Closes DR #5158.
<br>> Eddi's (excellent) work on finding factor levels, type coercion of
<br>> columns etc. are all retained.
<br>>
<br>> Please try it and write back if things aren’t working as it was before. The
<br>> tests that had to be fixed are extremely rare cases. I suspect there should
<br>> be minimal issue, if at all, in this version. However, I do find the changes
<br>> here bring consistency to the function.
<br>>
<br>> One (very rare) feature that is not available due to this implementation is
<br>> the ability to recycle.
<br>>
<br>> dt1 <- data.table(x=1:3, y=4:6, z=list(1:2, 1:3, 1:4))
<br>> lst1 <- list(x=4, y=5, z=as.list(1:3))
<br>>
<br>> rbind(dt1, lst1)
<br>> # x y z
<br>> # 1: 1 4 1,2
<br>> # 2: 2 5 1,2,3
<br>> # 3: 3 6 1,2,3,4
<br>> # 4: 4 5 1
<br>> # 5: 4 5 2
<br>> # 6: 4 5 3
<br>>
<br>> The 4,5 are recycled very nicely here.. This is not possible at the moment.
<br>> This is because the earlier rbind implementation used as.data.table to
<br>> convert to data.table, however it takes a copy (very inefficient on huge /
<br>> many tables). I’d love to add this feature in C as well, as it would help
<br>> incredibly for use within [.data.table (now that we can fill columns and
<br>> bind by names faster). Will add a FR.
<br>>
<br>> In summary, I think there should be minimal issues, if any and should be
<br>> much faster (for rbind cases). Please write back what you think, if you
<br>> happen to try out.
<br>>
<br>>
<br>>
<br>> Arun
<br>>
<br>>
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<br>> datatable-help@lists.r-forge.r-project.org
<br>> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
<br>
<br>
<br>
<br>--
<br>Statistics & Software Consulting
<br>GKX Group, GKX Associates Inc.
<br>tel: 1-877-GKX-GROUP
<br>email: ggrothendieck at gmail.com
<br></div></div></span></blockquote><p></p></body></html>