Prepping for useR! 2011 – tty connection update

July 22, 2011 | BioStatMatt

I'm putting together my presentation for useR! 2011 titled "Experimenting with a tty connection for R". Hence, I've updated the tty connection patch to work with R versions 2.13.0 and 2.13.1. And, instead of re-listing the patch files and re-writing instructions on their application, I've devoted a small portion of my Code page ... [Read more...]

R: calculations involving months

July 7, 2011 | nsaunders

Ask anyone how much time has elapsed since September last year and they’ll probably start counting on their fingers: “October, November…” and tell you “just over 9 months.” So, when faced as I was today with a data frame (named dates) like this: How to add a 7th column, with ... [Read more...]

Visualizing Periodic Data

June 28, 2011 | John Myles White

Yesterday the Princeton machine learning reading group went through a paper by Tukey on “Some graphic and semigraphic displays”. One issue we talked about at length was Tukey’s idiosyncratic approach to visualizing periodic data in a circular format to emphasize the connections between the “start” and the “end” of ... [Read more...]

ProjectTemplate News

June 25, 2011 | John Myles White

The news below was recently reported on the ProjectTemplate mailing list. For completeness, I’m also reporting it here. The first piece of ProjectTemplate news is that I won’t be the exclusive maintainer for ProjectTemplate anymore. Allen Goodman, who works at BankSimple, is now my co-maintainer and he has ... [Read more...]

Speeding Up MLE Code in R

June 18, 2011 | John Myles White

Recently, I’ve been fitting some models from the behavioral economics literature to choice data. Most of these models amount to non-linear variants of logistic regression in which I want to infer the parameters of a utility function. Because several of these models aren’t widely used, I’ve had ... [Read more...]

sas7bdat database reader update

June 14, 2011 | BioStatMatt

An earlier post (1216) introduced a compatibility study (i.e. reverse engineering) of the sas7bdat database file format. The code and documentation for this are here: I've recently restructured the code as an R package, and added some functionality. Look for the sas7bdat ... [Read more...]

Syntax highlighting of R code at

May 20, 2011 | nsaunders

If your WordPress blog is hosted at (like this one), you may know that source code in posts is formatted and highlighted using a shortcode, as explained here. Until recently, R was not on the list of supported languages (neither was Perl), but I noticed today that both ... [Read more...]

Friday fun projects

May 14, 2011 | nsaunders

What’s a “Friday fun project”? It’s a small computing project, perfect for a Friday afternoon, which serves the dual purpose of (1) keeping your programming/data analysis skills sharp and (2) providing a mental break from the grind of your day job. Ideally, the skills learned on the project are ... [Read more...]

making meat shares more efficient with R and Symphony

May 9, 2011 | Harlan

In my previous post, I motivated a web application that would allow small-scale sustainable meat producers to sell directly to consumers using a meat share approach, using constrained optimization techniques to maximize utility for everyone involved. In this post, I’ll walk through some R code that I wrote to ... [Read more...]

Comments on an R Connections API

May 9, 2011 | BioStatMatt

I wrote this post months ago but never hit 'Publish'. But, the subject has changed little since then. So, here's to cleaning out the draft folder... R's connections are the heart of data/code/text input and output. Without connections, R would be crippled. Additional connections make R more ... connected ... [Read more...]

Data Aggregation in R: plyr, sqldf and data.table

April 28, 2011 | hayward

I’ve also previously put up a couple of posts about aggregating data in R. In this post, I’m going to be trying some other alternative methods for aggregating the dataset. Before I begin, I’d like to thank Matthew Dowle for highlighting these to me. It’s a ... [Read more...]
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