A Draft of ProjectTemplate v0.2-1
I’ve just uploaded a new binary of ProjectTemplate to GitHub. This is a draft version of the next release, v0.2-1, which includes some fairly substantial changes and is backwards incompatible in several ways with previous versions of ProjectTemplate. Foremost of the changes is that most of the logic for load.project() is now built into the [...]
The NYC Marathon
New York’s annual marathon took place yesterday. Watching a bit of it on television with my friends, I was struck by the much earlier starting time for women than men. Specifically, professional women started running yesterday at 9:10 AM, while professional men start running at 9:40 AM. (This information comes from the runner’s handbook.) I [...]
Promising R Packages
As a quick note, here are two R packages that were mentioned to me recently and that look promising: reldist and mixtools.
EM and Regression Mixture Modeling
[UPDATE: As Will points out in the comments, this isn't really the EM algorithm. There isn't a proper E step, because there's no distribution being estimated: there's only a maximization step that alternates between maximizing the class labels and the slopes. You can think of this algorithm as a degenerate version of EM in the [...]
R Recommendation Contest Launches on Kaggle
The R Recommendation Engine contest is now live on Kaggle. Please head over there and start submitting your predictions for the test data set. Once you do, you can check the leaderboard to see how your algorithm compares with other people’s work. We know that there’s still plenty of progress that can be made, because [...]
Build a Recommendation System for R Packages
On Dataists, a new collaborative blog for data hackers that I’m contributing to, we’ve just announced a data contest that’s custom made for R users. To win the contest, you need to build a recommendation system for R packages. To find out more, check out the official announcement on Dataists. Then go to GitHub to [...]
ProjectTemplate Version 0.1-3 Released
I’ve just released the newest version of ProjectTemplate. The primary change is a completely redesigned mechanism for automatically loading data. ProjectTemplate can now read compressed CSV files, access CSV data files over HTTP, read Stata, SPSS and RData binary files and even load MySQL database tables automatically. For my own projects, this is a big [...]
Two New R Packages: log4r and SortableHTMLTables
I’ve just released two new packages for R: log4r and SortableHTMLTables. log4r is a minimal logging utility for R that’s inspired by the log4j family of logging tools. It has substantially fewer features than other logging tools for R, but it’s hopefully easier to use. SortableHTMLTables uses brew and the jQuery Tablesorter plugin to provide [...]
Higher Order Functions in R
Introduction Because R is, in part, a functional programming language, the ‘base’ package contains several higher order functions. By higher order functions, I mean functions that take another function as an argument and then do something with that function. If you want to know more about the usefulness of writing higher order functions in general, [...]
Doing Maximum Likelihood Estimation by Hand in R
Lately I’ve been writing maximum likelihood estimation code by hand for some economic models that I’m working with. It’s actually a fairly simple task, so I thought that I would write up the basic approach in case there are readers who haven’t built a generic estimation system before. First, let’s start with a toy example [...]