Blog Archives

You should not use split in production code

June 7, 2012
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Recently I have stumbled on a problem with split function applied on list of factors. The issue is that it might produce wrong splits when splitting factors contain dots.Here is the example of the problem. Invoking the following code:df <-...

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Visualizing car brand choices in ggplot2

June 2, 2012
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Visualizing car brand choices in ggplot2

I always like to read new posts at chartsnthings as they always inspire me with new ideas for data visualization. Yesterday I have read an article on choices of car brands by members of parliament in Poland in Gazeta.pl. It contains a simple ...

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Cross-valitation variability example, part I

May 26, 2012
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Cross-valitation variability example, part I

Recently I had a discussion with a student about variability of results obtained from cross-validation procedure. While the subject is well known there are not many examples on the web showing it, so I have written its simple presentation.Results from ...

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Emulating local static variables in R

May 17, 2012
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Emulating local static variables in R

Recently I was writing a code allowing to plot multiple ggplot2 plots on one page. I wanted to replicate standard behavior of  plot  function that plots graphs in sequence according to  mfrow/ mfcol option in par...

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Porting cdplot to ggplot2

May 11, 2012
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Porting cdplot to ggplot2

Last week I published a post on plotting tables in ggplot2. So the next natural step is to port cdplot to allow simple visualization of categorical variables against a numerical predictor.First part of the story covers binary variables. In th...

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Visualizing tables in ggplot2

May 5, 2012
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Visualizing tables in ggplot2

Recently I wanted to recreate  assocplot  using  ggplot2. In the end I propose a simple way to visualize data arranged two-way tables using geom_tile.I used Titanic data set as an example combining age and sex dimensi...

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Animating Schelling’s segregation model

April 29, 2012
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Animating Schelling’s segregation model

Recent blog post on Animations in R inspired me to write a code that generates animations of simulation model. For this task I have chosen Schelling's segregation model.Having written the code I have found that one year ago a similar code has been...

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Generating all subsets of a set

April 20, 2012
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Generating all subsets of a set

Recently I have calculated Banzhaf power index. I required generation of all subsets of a given set. The code given there was a bit complex and I have decided to write a simple function calculating it. As an example of its application I reproduce Figur...

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Plotting conditional densities

April 14, 2012
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Plotting conditional densities

Recently I have read a post on Comparing all quantiles of two distributions simultaneously on R-bloggers. In the post author plots two conditional density plots on one graph. I often use such a plot to visualize conditional densities of score...

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Comparing Banzhaf and Shapley-Shubik power indices

March 22, 2012
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Comparing Banzhaf and Shapley-Shubik power indices

Last week I analyzed Shapley-Shubik power index in R. I got several requests to write a code calculating Banzhaf power index. Here is the proposed code.Again I use data from Warsaw School of Economics rector elections (the details are in my last post)....

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