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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Result.dt<-dt[ , list(sd.dtable=dtable(.SD)), by=trichotomous.variable] # untested<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">will return a Result.dt with 2 columns: trichotomous.variable and sd.dtable<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The value of Result.dt[1,sd.dtable][[1]] will give the 1st groups dtable results<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">~malcolm_cook@stowers.org<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> datatable-help-bounces@lists.r-forge.r-project.org [mailto:datatable-help-bounces@lists.r-forge.r-project.org]
<b>On Behalf Of </b>Farrel Buchinsky<br>
<b>Sent:</b> Friday, October 20, 2017 1:14 PM<br>
<b>To:</b> datatable-help@lists.r-forge.r-project.org<br>
<b>Subject:</b> [datatable-help] Generating data.tables from a j function<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I am relatively certain that data.table can handle a function in the J position that generates a data.frame or a data.table. However, how does one handle the output? Can you please point me to a url that discusses the capability?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">For instance, I sometimes use the package dtables to generate descriptive statistics. It generates a table for <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">So one could go<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">library(dtables)<o:p></o:p></p>
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<p class="MsoNormal">dtable(dt)<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">But what if one wanted to get descriptive statistics by a trichotomous variable<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">dt[ , dtable(.SD), by=trichotomous.variable]<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>I am looking for a general article or blogpost about how to handle outputs that are not single numbers or two numbers.
</b>There are functions that yield data.tables or lists or specialized objects such a models. Any suggestions?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I know one can simply print the output to the console<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">dt[ , print(dtable(.SD)_, by=trichotomous.variable] <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">But that does not let me do anything intelligent afterwards. <o:p></o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
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<p class="MsoNormal">Farrel Buchinsky<o:p></o:p></p>
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<p class="MsoNormal">(412) 567-7870 (gets me everywhere)<o:p></o:p></p>
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