Yesterday I surfed the web looking for 3D wireframe examples to explain linear models in class. I stumbled across this site where animated 3D wireframe plots are outputted by SAS.  Below I did something similar in R. This post shows the few steps of how to create an animated .gif file using R and ImageMagick. Here I assume that you have ImageMagick installed on your computer. As far as I know it is also possible to produce animated .gif files using R only, e.g. with write.gif() from the caTools package. But using ImageMagick is straighforward, gives you control over the conversion and .gif production and is the free standard program for conversion. Continue reading ‘Animate .gif images in R / ImageMagick’


Abilities of R for creating graphics is great, but one thing I always missed is the possibility of creating interactive plots and being able to look at graphs while changing one ore more parameters. I know that there is rggobi, but so far I always ran into problems with flexibility each time I wanted to use it. So I kept on searching until I found playwith which is “an R package, providing a GTK+ graphical user interface for editing and interacting with R plots” as its homepage says. The homepage includes a lot of screenshots with code snippets so this post doesn’t intend to give an extensive review about the possibilities of the playwith package to the reader. All I want to do now is present a small application of it. Continue reading ‘Playing with the ‘playwith’ package’


At the institute I’m working quite a lot of people prefer using Matlab and only a few of them know about R. Today one of my colleagues — who is also an eager user of Matlab — ran into the following problem:

  • He had a vector v in hand which consisted of \frac{n(n+1)}{2} elements.
  • He wanted to reshape this data into an n×n matrix M, where the element M_{ij} is equal to v_{k+j}I(j<=n-i+1) with k=\frac{(2n-i+2)(i-1)}{2} and I(j <= n-i+1)=1 if the condition j <= n-i+1 is satisfied and 0 otherwise. In other words, the first (n-i+1)th element of the ith row of M is equal to the vector (v_{k+1},v_{k+2},\ldots,v_{k+n-i+1}) and the remaining elements are zero.

He struggled for long minutes of how he should design a loop for doing this task. Of course writing such a loop is not a highly difficult task, but why would we waste our time, if we can get the same result in a single line of R code?

Continue reading ‘R vs. Matlab – a small example’


Update (2014/08/24): Since October 2013 the pbapply package is available that has picked up the idea of integrating progress bars into the apply family of functions outlined in this post.

In a previous post I gave some examples of how to make a progress bar in R. In the examples the bars were created within loops. Very often though I have situations where I would like have a progress bar when using apply(). The plyr package provides several apply-like functions also including progress bars, so one could have a look here and use a plyr function instead of apply if possible. Anyway, here comes a wrapper for apply, lapply and sapply that has a progressbar. It seems to work although one known issue is the use of vectors (like c(1,2)with the MARGIN argument in apply_pb(). Also you can see in the performance comparison below that the wrapper causes overhead to a considerable extent, which is the main drawback of this approach. Continue reading ‘Progress bars in R (part II) – a wrapper for apply functions’


germany_by_unemployment_shapefileLately, David Smith from REvolution Computing set out to challenge the R community with the reprocuction of a beautiful choropleth map (= multiple regions map/thematic map) on US unemployment rates he had seen on the Flowing Data blog. Here you can find the impressing results. Being a fan of beautiful visualizations I tried to produce a similar map for Germany. Continue reading ‘Infomaps using R – Visualizing German unemployment rates by district on a map’


regression_models_in_latexMost people using LaTex feel that creating tables is no fun. Some days ago I stumbled across a neat function written by Paul Johnson that produces LaTex code as well as LaTex code that can be used within Lyx. The output can be used for regression models and looks like output from the Stata outreg command. His R function that produces the LaTex code has the same name:  outreg(). The outreg code can be found on his website or in the PDF copy of the code from his website.

I took the code, put it into a .rnw file and sweaved it. It worked like a charm and produced beautiful results (see the picture on the left and the PDF). Below you can find the code for the noweb file (.rnw). Latex code is colored grey, R-code is colored blue. Just have a look at all the results as a PDF file. Besides, Paul Johnson has also created a nice list of R-Tips that can be found on his website as well.

Continue reading ‘R: Function to create tables in LaTex or Lyx to display regression model results’


Just a little note for german speaking R beginners: There is an introductory course in R (german) available online on the website of the department of methodology and evaluation research at the University of Jena. Dr. Ivailo Partchev holds a seven sessions course on that topic (duration 11.5 hours).



Follow

Get every new post delivered to your Inbox.

Join 59 other followers