mages' blog

Following on from last week's post, here are my slides on using googleVis on shiny from the Advanced R workshop at Lancaster University, 21 May 2013.

googleVis on shiny

Again, I wrote my slides in RMarkdown and I used slidify to create the HTML5 presentation. Unfortunately you may have to reload the slides that use googleVis on shiny as the JavaScript code in the background is potentially not ideal. Any pointers, which could help to improve the performance will be much appreciated.

Many of the examples in my slides are taken from my post First steps of using googleVis on shiny, however the presentation also demonstrates that it is possible to inject JavaScript code into a googleVis chart to trigger a shiny event, see also the example below.

Our 5th Cologne R user group meeting was the best attended meeting so far, with 20 members finding their way to the Institute of Sociology for two talks by Diego de Castillo on shiny and Stephan Holtmeier on cluster analysis, followed by beer and schnitzel at the Lux, a gastropub nearby.

Shiny

Diego gave an overview of the design principles behind shiny, which provides a powerful API to build web apps in pure R. His explanation of the reactive programming model was particularly helpful to understand how shiny works under the hood and why it is so responsive. His live demonstrations of shiny even included shiny server, which he had running in a virtual machine. Diego's slides are available via our Meetup site.

Diego de Castillo: Introduction to shiny

You can hear more from Diego and me at the UseR!2013 conference in Albacete, where we will give a googleVis tutorial. We will touch on googleVis on shiny as well. A dedicated shiny tutorial will be given in the afternoon by Josh and Winston from RStudio.

Cluster analysis

Stephan Holtmeier, who is a psychologist by background, presented an introduction to cluster analysis with R, motivated by his work in analysing survey data. As a toy example he used a 360° feedback survey of a group of managers within a big company. In his example he wanted to understand the profile of those managers better. Stephan illustrated how a cluster analysis can help to identify groups of managers with similar strengths, e.g. for communication, leadership and/or performance. Depending on how he measured the distance between managers he could look for people who have similar levels of competency or a similar profile (correlation). Stephan also touched on the differences between hierarchical and centroid based cluster analysis, such as k-means. You can find Stephan's slides (in German) also on our Meetup site.

Stephan Holtmeier: Cluster Analysis with R

For more information on cluster analysis functions in R see also the cluster task view on CRAN. If you would like to get an overview of how psychologists look at data, then check out William Revelle's vignette of the psych package. Finally, if you are interested in how a k-means cluster analysis can be used for image manipulation, see an earlier post of mine.

Next Kölner R meeting, 19 July 2013

The next meeting has been scheduled for 19 July. Günter Faes will present his experiences using the XLConnect package as an interface between R and Excel. Dietmar Janetzko agreed to present how he used R and Twitter to predict exchange rate movements. Of course, the evening will close with a few Kölsch in a nearby beer-garden.

Please get in touch if you would like to present and share your experience, or indeed if you have a request for a topic you would like to hear more about. For more details see also our Meetup page.

Thanks again to Bernd Weiß for hosting the event and Revolution Analytics for their sponsorship.

The new version of googleVis 0.4.2 is now available via CRAN. Many thanks to all who provided feedback on version 0.4.0 and particularly to Sebastian Campbell, John Maindonald and Aonan Zhang. As usual, if you find any issues or bugs, please send us an email or add a line to our online issues log.

With version 0.4.0 we introduced support for googleVis on shiny. See my previous post for more details and examples.

The CRAN release of googleVis 0.4.2 has some further improvements:

• New shiny and FAQ sections in package vignette
• Core charts (e.g. line, area, scatter, bar, column and combo charts) accept now also date variables for the x-axis
  
• Typos in the Stock and Andrew data sets have been fixed
  
• The WorldBank demo uses now the WDI package to download data from the World Bank, see the R code below
  

The guys at RStudio have done a fantastic job with shiny. It is really easy to build web apps with R using shiny. With the help of Joe Cheng from RStudio we figured out a way to make googleVis work on shiny as well. This allows you to make use of the Google Charts Tools in your shiny app directly from R. What I present here are three initial examples which seem to work in most browsers. The third example even uses a neat trick to create an animated geo chart.



However, before we upload the next version of googleVis to CRAN we decided to present a preview of version 0.4.0 here, asking for feedback. It would not be fair on the guys behind CRAN to release something into the wild, only to be told by users within a few days that we missed something. Hence, you can get the new version of googleVis only from the download page of our project site for the time being.

You may have read the post on RStudio's blog that the shiny API changed slightly: the reactivePlot and reactiveText functions have been renamed to renderPlot and renderText with simplified input parameters. Thanks to Joe, there is now also a renderGvis function as part of the googleVis package, which works in very much the same way as the other two.

To run the following examples you need shiny version 0.4.0 and googleVis version 0.4.0 or higher.