Last Friday the Cologne R user group came together for two talks and a quiz at Eye/o, the company behind Adblock Plus, in Köln-Ehrenfeld. Eye/o were a great host, offering nibbles and drinks to warm up the event and pizza in the end.

Cologne R user meeting at Eye/o

The first talk was given by Jiddu Alexander, a physicist turned freelance data scientist. Jiddu gave an introduction into the tidyverse. He presented the concept of tidy data, and how the tidyverse 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 web site.

Jiddu Alexander explaining learning curves

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 Rprof function of the utils package can be used to understand the performance profile of R code. Furthermore, the microbenchmark package with a function of the same name can then be used to test new approaches for a code block.

Nils Glück quoting others who are not bothered about performance

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 R Inferno book by Pat Burns.

Next Kölner R meeting

The next meeting will be scheduled in about three months time. Details will be published on our Meetup site. Thanks again to Eye/o for their support.

Please get in touch, if you would like to present at the next meeting.