<p><div><div><div><div data-width="100" data-show-faces="false" data-send="true" data-layout="button_count" data-height="21" data-href="https://www.r-bloggers.com/notes-from-the-kolner-r-meeting-14-october-2016/"></div></div><div><a data-url="https://www.r-bloggers.com/notes-from-the-kolner-r-meeting-14-october-2016/" data-counturl="https://www.r-bloggers.com/notes-from-the-kolner-r-meeting-14-october-2016/" data-count="horizontal" data-text="Notes from the Kölner R meeting, 14 October 2016" class="twitter-share-button" data-via="rbloggers" href="https://twitter.com/share"></a></div><div></div></div><div></div></div>
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(This article was first published on <strong><a href="http://www.magesblog.com/2016/10/notes-from-kolner-r-meeting-14-october.html"> mages' blog</a></strong>, and kindly contributed to <a rel="nofollow" href="https://www.r-bloggers.com/">R-bloggers)</a> </div>
<p>Last Friday the Cologne R user group came together for two talks and a quiz at <a target="_blank" rel="nofollow" href="https://eyeo.com/">Eye/o</a>, the company behind <a target="_blank" rel="nofollow" href="https://adblockplus.org/">Adblock Plus</a>, in Köln-Ehrenfeld. Eye/o were a great host, offering nibbles and drinks to warm up the event and pizza in the end.</p>
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<td>Cologne R user meeting at Eye/o</td>
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<p>The first talk was given by <a target="_blank" rel="nofollow" href="http://www.jiddualexander.com/">Jiddu Alexander</a>, a physicist turned freelance data scientist. Jiddu gave an introduction into the <a target="_blank" rel="nofollow" href="https://cran.r-project.org/package=tidyverse">tidyverse</a>. He <a target="_blank" rel="nofollow" href="http://www.jiddualexander.com/blog/tidyverse_presentation/">presented</a> the concept of tidy data, and how the <code>tidyverse</code> bundle can be used to manage multiple models. Furthermore, he explained the concept of learning curves for model selection. Jiddu’s slides are available from his <a target="_blank" rel="nofollow" href="http://www.jiddualexander.com/blog/tidyverse_presentation/">web site</a>.<br><br>
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<td>Jiddu Alexander explaining learning curves</td>
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<p>Next up was Nils Glück to share his experience on performance profiling. R code often grows from a small idea for a specific task to a longer and longer script as more and more ideas and use cases are added. Occasionally, we end up with a long and poorly documented script that ‘does the job’ but has become slow. Finding the bottlenecks and addressing them is good short term remedy. Nils showed us how the <code>Rprof</code> function of the <code>utils</code> package can be used to understand the performance profile of R code. Furthermore, the <code>microbenchmark</code> package with a function of the same name can then be used to test new approaches for a code block.</p>
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<td>Nils Glück quoting others who are not bothered about performance</td>
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<p>To bridge the time for the pizzas to arrive our host Kirill had prepared a little R quiz: Could we guess the output of simple R statements? Well, it is more difficult than you might think. Kirill had a great selection of quirky one-liners, which he had collected over time and borrowed from the fabulous <i><a target="_blank" rel="nofollow" href="http://www.burns-stat.com/documents/books/the-r-inferno/">R Inferno</a></i> book by <a target="_blank" rel="nofollow" href="http://www.burns-stat.com/">Pat Burns</a>.</p>
<h3>Next Kölner R meeting</h3>
<p>The next meeting will be scheduled in about three months time. Details will be published on our <a target="_blank" rel="nofollow" href="http://www.meetup.com/KoelnRUG/">Meetup site</a>. Thanks again to <a target="_blank" rel="nofollow" href="https://eyeo.com/">Eye/o</a> for their support.</p>
<p>Please <a target="_blank" rel="nofollow" href="http://www.magesblog.com/p/contact.html">get in touch</a>, if you would like to present at the next meeting.
<div>This post was originally published on <a target="_blank" rel="nofollow" href="http://www.magesblog.com/">mages’ blog</a>.</div>
<p><div><div><div><div data-width="55" data-show-faces="false" data-send="true" data-layout="box_count" data-height="62" data-href="https://www.r-bloggers.com/notes-from-the-kolner-r-meeting-14-october-2016/"></div></div><div><a data-url="https://www.r-bloggers.com/notes-from-the-kolner-r-meeting-14-october-2016/" data-counturl="https://www.r-bloggers.com/notes-from-the-kolner-r-meeting-14-october-2016/" data-count="vertical" data-text="Notes from the Kölner R meeting, 14 October 2016" class="twitter-share-button" data-via="rbloggers" href="https://twitter.com/share"></a></div><div></div></div><div></div></div>
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