September 2012

Fitting an ellipse to point data

September 30, 2012 | Michael Bedward

Some time ago I wrote an R function to fit an ellipse to point data, using an algorithm developed by Radim Halíř and Jan Flusser1 in Matlab, and posted it to the r-help list. The implementation was a bit hacky, returning odd results for some data. A couple of days ... [Read more...]

Working with Bipartite/Affiliation Network Data in R

September 30, 2012 | Solomon

Data can often be usefully conceptualized in terms affiliations between people (or other key data entities). It might be useful analyze common group membership, common purchasing decisions, or common patterns of behavior. This post introduces bipartite/affiliation network data and provides … Continue reading →
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Football, an ordinal model

September 30, 2012 | Wingfeet

On September 19th, flo2speak remarked under a post that his/her experience is that ordinal models had better performance. That seems reason enough to try, so there we are. In examining this type of model it is found that more complex models can be...
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Plot R Data With googleVis

September 30, 2012 | Andrew Barr

Here is a little code snippet that shows how to do two things Use the Google Maps API to resolve place names into lat-long coordinate pairs. Plot R dataframes that contain lat-long data (for example from #1) onto Google Maps for quick visualization using the googleVis package.  The embedded map looks ... [Read more...]

Quantifying student feedback using Org mode and R

September 30, 2012 | Greg

As the term has progressed, my LSM2241 lectures are getting more consistent. I’m aiming to use 45 slides for what is officially a two hour lecture, although in reality it lasts about 90 minutes. We take a break at about 50 … Continue reading → [Read more...]

my Facebook social network

September 29, 2012 | Michael kao

I got very excited on making a network diagram of my Facebook network using Ghefi (https://gephi.org/) and submitted my first assignment for the Social Network Analysis course on https://www.coursera.org/. It's middle of the night, so I will ... [Read more...]

Padding integers for use in filenames

September 29, 2012 | Corey Chivers

If you’ve ever written code that generates a whole whack of files, you may have came across the following problem when processing them. Using a naming convention wherein files are numbered will  gum up any ordering which is based on string sorting (ls, for example). What you end up ... [Read more...]

Merging Dataframes by Partly Matching String

September 29, 2012 | Kay Cichini

The latest posting by Tony Hirst sparked my attention because I was thinking about a very similar issue recently.I was also fiddling around with agrep and adist until I realised that for this very issue matching of substrings is not as important as matching multiple words.. With this different ... [Read more...]

Weekend Reading – Gold in October

September 28, 2012 | systematicinvestor

I recently came across the “An early Halloween for gold traders” article by Mark Hulbert. I have discussed this type of seasonality analysis in my presentation at R/Finance this year. It is very easy to run the seasonality analysis using the Systematic Investor Toolbox. This confirms that October have ... [Read more...]

Browse the in-development R sources at GitHub

September 28, 2012 | David Smith

As an open-source project, the R source code has always been available to download from the R-project website. You can find source code for the latest released version here, and for the changing-daily new version in progress (R-devel) here. But if you don't have the R sources handy, and just ... [Read more...]

Second Milano R net meeting

September 28, 2012 | Milano R net

Second Milano R net meeting took place on September, 27. More than thirty R users joining both the presentations session and the open bar. If you attended the meeting, please leave a comment in the page of the meeting. You … Continue reading → [Read more...]

Optimal seriation for your matrices

September 28, 2012 | is.R()

In our previous post, we used a quick-and-dirty method for ordering the axes on our heatmap. It has been pointed out to me that There is a Package for That (which is my nominee for a new slogan for R — not that it needs a slogan). seriation offe... [Read more...]

Presentations of the second Milano R net meeting

September 28, 2012 | Milano R net

Welcome presentation Andrea Spanò, Partner at Quantide (download PDF, 3.0 MB) Introduction to the next Italian BioR event at PTP Andrea Pedretti, Parco Tecnologico Padano (download PDF, 0.2 MB) Applications of technical risk assessment in Food Industry by R Carlo … Continue reading → [Read more...]

3-D animation of the changing Antarctic ice sheet

September 27, 2012 | David Smith

Last month we shared an visualization showing the changing extent of Arctic sea-ice. This visualization by the multinational Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) switches the view to the Southern pole and takes the visualization to a whole new level, by animating it in 3-D: The ... [Read more...]

Histogram + Density Plot Combo in R

September 27, 2012 | Mollie

Plotting a histogram using hist from the graphics package is pretty straightforward, but what if you want to view the density plot on top of the histogram? This combination of graphics can help us compare the distributions of groups.Let's use... [Read more...]

Set package repositories at startup

September 27, 2012 | Henrik Bengtsson

The below code shows how to configure the 'repos' option in R such that install.packages() etc will locate the packages without having to explicitly specify the repository.  Just add it to the .Rprofile file in your home directory (iff missing, create it). For more details, see help("Startup").local({ ... [Read more...]
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