Blog Archives

BioStar users (of the world, unite)

October 9, 2010
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BioStar users (of the world, unite)

Egon writes: Can someone please plot the BioStar users on a Google Map? Sounds like a challenge. Let’s go. 1. Harvesting user IP addresses BioStar user profiles (here’s mine) include a location field. It’s free text and optional, which means that location is missing or inaccurate for many users. However, if you’re logged into BioStar

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Connecting to a MongoDB database from R using Java

September 24, 2010
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Connecting to a MongoDB database from R using Java

It would be nice if there were an R package, along the lines of RMySQL, for MongoDB. For now there is not – so, how best to get data from a MongoDB database into R? One option is to retrieve JSON via the MongoDB REST interface and parse it using the rjson package. Assuming, for

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GEO database: curation lagging behind submission?

August 30, 2010
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GEO database: curation lagging behind submission?

I was reading an old post that describes GEOmetadb, a downloadable database containing metadata from the GEO database. We had a brief discussion in the comments about the growth in GSE records (user-submitted) versus GDS records (curated datasets) over time. Below, some quick and dirty R code to examine the issue, using the Bioconductor GEOmetadb

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Abstract word clouds using R

August 23, 2010
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Abstract word clouds using R

A recent question over at BioStar asked whether abstracts returned from a PubMed search could easily be visualised as “word clouds”, using Wordle. This got me thinking about ways to solve the problem using R. Here’s my first attempt, which demonstrates some functions from the RCurl and XML packages. update: corrected a couple of copy/paste

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A brief introduction to “apply” in R

August 19, 2010
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A brief introduction to “apply” in R

At any R Q&A site, you’ll frequently see an exchange like this one: Q: How can I use a loop to ? A: Don’t. Use one of the apply functions. So, what are these wondrous apply functions and how do they work? I think the best way to figure out anything in

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Analysing the ISMB 2010 meeting using R

July 20, 2010
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Analysing the ISMB 2010 meeting using R

The colossus of bioinformatics meetings, ISMB, convened in Boston this year from July 9 – 13. As in recent years, the meeting was covered online at its website, FriendFeed and Twitter. I thought it would be fun to run a quick analysis of activity at the FriendFeed room using R. 1. Fetch the data We

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biomaRt and GenomeGraphs: a worked example

June 6, 2010
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biomaRt and GenomeGraphs: a worked example

As promised a few posts ago, another demonstration of the excellent biomaRt package, this time in conjunction with GenomeGraphs. Here’s what we’re going to do: Grab some public microarray data Normalise and get a list of the most differentially-expressed probesets Use biomaRt to fetch the genes associated with those probesets Plot the data using GenomeGraphs

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Beware of rogue header files (Bioconductor installation)

May 11, 2010
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Beware of rogue header files (Bioconductor installation)

Just a short note concerning a “gotcha”. As I have many times before, I opened an R console on my newly-upgraded (to lucid 10.04) Ubuntu machine, typed source(“http://bioconductor.org/biocLite.R”) and began a Bioconductor install with biocLite(). Only this time, I saw this: Error in dyn.load(file, DLLpath = DLLpath, ...) : unable to load shared library '/home/sau103/R/i486-pc-linux-gnu-library/2.11/affyio/libs/affyio.so':

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Experiments with igraph

April 21, 2010
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Experiments with igraph

Networks – social and biological – are all the rage, just now. Indeed, a recent entry at Duncan’s QOTD described the “hairball” network representation as the dominant cultural icon in molecular biology. I’ve not had occasion to explore networks “professionally”, but have always been fascinated by both networks and the tools used to analyse them.

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Getting your web application and R(Apache) to talk to each other

April 19, 2010
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Getting your web application and R(Apache) to talk to each other

Here’s the situation. Web applications, built using a framework (e.g. Rails, Django) are great for fetching data from a database and rendering it. They’re not so great for crunching and charting the data. Conversely, R is great for crunching and charting, but doesn’t make for a great web application. The idea then, is to let

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