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R is fairly slow in reading files. read.table() is slow, scan() a bit faster, and readLines() fastest.But all these are nowhere as fast as other tools that scan through files. Let us look at an example. I have in front of me a 283M file.(Small update: the ... [Read more...]

When learning R it is helpful to have your own personal help file. One you create for yourself, with the notes, links, and language you understand (sometimes the help files are not very helpful). Let me introduce you to Tomboy Notes.Tomboy Notes is a l... [Read more...]

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 ... [Read more...]

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 ... [Read more...]

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 [...] [Read more...]

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 ... [Read more...]

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... [Read more...]

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 ... [Read more...]

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 ... [Read more...]

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, ... [Read more...]

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 ... [Read more...]

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 ... [Read more...]

Monday August 01 was the first full day of JSM 2011 and full is the appropriate word to describe the day! It started for me at 7am with a round table run by Marc Suchard on parallel computing (or at 3am if I am considering the time I woke up!). I was ... [Read more...]

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LaTeX is very strong for typesetting mathematical equations. Fast Tube by Casper Other useful resources are provided on the Supplementary Material page. [Read more...]

A week or so ago I saw a tweet related how the NFL lockout was affecting the search traffic for “fantasy football” on Google (using Google Trends).  Basically, the search traffic (properly normalized on Google Trends) was down prior to … Continue reading → [Read more...]

This week the reader is directed to Messy Matters to read up on research conducted by Sharad Goel, Duncan Watts and Dan Goldstein in which they hunted for traces of "viral" diffusion on Twitter, Facebook, Yahoo!, and beyond. The results run counter to mainstream intuition. [Read more...]