Monthly Archives: August 2011

Data Driven Story Discovery: Working Up a Multi-Layered Chart

August 3, 2011
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Data Driven Story Discovery: Working Up a Multi-Layered Chart

How many different dimensions (or “columns” in a dataset where each row represents a different sample and each column a different measurement taken as part of that sample) can you plot on a chart? Two are obvious: X and Y values, which are ideal for representing continuous numerical variables. If you’re plotting points, as in

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WordPress WordCloud with R

August 3, 2011
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WordPress WordCloud with R

These days one can frequently read about wordclouds created with R, initiated by the release of the wordcloud package by Ian Fellows on July 23rd. So here I am to put in my two cents. I thought about creating a wordcloud of a complete blog history, so I build a script that connects to a

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RTextTools v1.1 Released

A major upgrade of RTextTools has been released, including many optimizations, UI changes, and features based on feedback from the 2011 CAP Conference in Catania. Changes include the addition of a new low-memory algorithm GLMNET, full user documentation, simplification of the user interface, bundled datasets, better analytics for both virgin a

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Are students’ teaching evaluations influenced by instructors’ looks?

August 3, 2011
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Are students’ teaching evaluations influenced by instructors’ looks?

Are students' teaching evaluations influenced by instructors' looks? ggplot2 may help find the answer.The recent release of RcmdrPlugin.KMggplot2 has made ggplot2 available to those who prefer GUI to the command line interface. With the new plugin for ...

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RcppArmadillo 0.2.28

August 2, 2011
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Armadillo 2.2.1 came out today (and it looks like 2.2.0 was skipped, tst, tst). It has now been wrapped into release 0.2.28 of RcppArmadillo which is already on CRAN. The NEWS entry is below; a number of these changes were already in the preceding 0...

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Syntax highlighting of roxygen documentation in TextMate

August 2, 2011
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With roxygen now on github, the release of roxygen2 and Hadley’s might now behind the project I expect roxygen to gain even more momentum. R development in TextMate is great with the R bundle. Unfortunately the R bundle does not support highlighting of roxygen documentation by default. That was always a sticking point for me

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Using Emacs to work with R

August 2, 2011
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Using Emacs to work with R

A simple yet efficient way to work with R consists in writing R code with your favorite text editor and sending it to the R console. This allows to build efficient R code in an incremental fashion. A good editor might even provide syntax highlighting, parenthesis matching, and a way to send a selected portion of code to R

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With byte compiler, R 2.14 will be even faster

August 2, 2011
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In a presentation at the JSM 2011 conference in Miami yesterday, R core member Luke Tierney revealed that the next major update to R, R 2.14, will feature improved speed when processing interpreted R code, thanks to standard use of the new byte compiler feature. The byte compiler was introduced with R 2.13, but while R developers could use...

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Summarizing Returns with R

August 2, 2011
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Summarizing Returns with R

Often I like to see the performance of a trading strategy summarized annually, quarterly or by month. In R, we start off with the summary function: Given a series xx, usually a chunk of the original, this function returns the accumulative returns for the period. The leverage is useful to somewhat simulate leveraged ETFs. The

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Merging Two Different Datasets Containing a Common Column With R and R-Studio

August 2, 2011
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Merging Two Different Datasets Containing a Common Column With R and R-Studio

Another way for the database challenged (such as myself!) for merging two datasets that share at least one common column… This recipe using the cross-platform stats analysis package, R. I use R via the R-Studio client, which provides an IDE wrapper around the R environment. So for example, here’s how to merge a couple of

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