<div dir="ltr">Hello Steve and thanks for your reply. I am running data.table_1.8.11<div><br></div><div>Full details below:<div><br></div><div><div>> sessionInfo()</div><div>R version 3.0.2 (2013-09-25)</div><div>Platform: x86_64-w64-mingw32/x64 (64-bit)</div>
<div><br></div><div>locale:</div><div>[1] LC_COLLATE=English_United Kingdom.1252 LC_CTYPE=English_United Kingdom.1252 </div><div>[3] LC_MONETARY=English_United Kingdom.1252 LC_NUMERIC=C </div>
<div>[5] LC_TIME=English_United Kingdom.1252 </div><div><br></div><div>attached base packages:</div><div>[1] stats graphics grDevices utils datasets methods base </div><div><br></div><div>other attached packages:</div>
<div> [1] timeDate_3010.98 data.table_1.8.11 quantstrat_0.7.8 </div><div> [4] foreach_1.4.1 blotter_0.8.15 PerformanceAnalytics_1.1.1</div><div> [7] FinancialInstrument_1.1 quantmod_0.4-0 Defaults_1.1-1 </div>
<div>[10] TTR_0.22-0 xts_0.9-5 zoo_1.7-10 </div><div><br></div><div>loaded via a namespace (and not attached):</div><div>[1] codetools_0.2-8 grid_3.0.2 iterators_1.0.6 lattice_0.20-23 plyr_1.8 </div>
<div>[6] reshape2_1.2.2 stringr_0.6.2 tools_3.0.2 </div></div></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Nov 22, 2013 at 2:50 PM, Steve Lianoglou-2 [via R] <span dir="ltr"><<a href="/user/SendEmail.jtp?type=node&node=4680970&i=0" target="_top" rel="nofollow" link="external">[hidden email]</a>></span> wrote:<br>
<blockquote style='border-left:2px solid #CCCCCC;padding:0 1em' class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">
Hi Daniel,
<br><br>On Fri, Nov 22, 2013 at 6:15 AM, daniel.krizian
<br></div><div class="im"><<a href="http://user/SendEmail.jtp?type=node&node=4680967&i=0" rel="nofollow" link="external" target="_blank">[hidden email]</a>> wrote:
<br>> Hello, I have:
<br>>
<br>> DT <- data.table(a=1:10, b=1:10,c=1:10, key=c("a","b"))
<br>> key(DT) # [1] "a" "b"
<br>> key(DT[,list(a,b)]) # NULL
<br>>
<br>> Note that DT loses its key when I select a subset of columns like above.
<br>>
<br>> Is this a (known) bug/ expected result?
<br><br></div><div class="im">The key is retained for me when I run your code:
<br><br>R> key(DT[,list(a,b)])
<br>[1] "a" "b"
<br><br>What version of data.table are you using?
<br><br>-steve
<br><br>--
<br>Steve Lianoglou
<br>Computational Biologist
<br>Genentech
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