Posts Tagged ‘ research diary ’

R: calculations involving months

July 7, 2011
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R: calculations involving months

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 the number of months between

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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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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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I’d be more than happy with the unlinked data web

April 14, 2010
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I’d be more than happy with the unlinked data web

Visit this URL and you’ll find a perfectly-formatted CSV file containing information about recent earthquakes. A nice feature of R is the ability to slurp such a URL straight into a data frame: quakes <- read.csv("http://neic.usgs.gov/neis/gis/qed.asc", header = T) colnames(quakes) # "Date" "TimeUTC" "Latitude" "Longitude" "Magnitude" "Depth" # number of recent quakes nrow(quakes) #

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BioMart (and biomaRt)

March 26, 2010
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BioMart (and biomaRt)

I’ve been vaguely aware of BioMart for a few years. Inexplicably, I’ve only recently started to use it. It’s one of the most useful applications I’ve ever used. The concept is simple. You have a set of identifiers that describe a biological object, such as a gene. These are called filters. They have values –

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A new twist on the identifier mapping problem

January 11, 2010
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A new twist on the identifier mapping problem

Yesterday, Deepak wrote about BridgeDB, a software package to deal with the “identifier mapping problem”. Put simply, biologists can name a biological entity in any way that they like, leading to multiple names for the same object. Easily solved, you might think, by choosing one identifier and sticking to it, but that’s apparently way too

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A brief survey of R web interfaces

November 29, 2009
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A brief survey of R web interfaces

I’m looking at ways to provide access to R via a web application. First rule: see what’s available first, before you reinvent the wheel. It’s not pretty. From the R Web Interfaces FAQ: Software Brief notes Rweb Page last updated 1999. Of the 3 example links on the page one ran very slowly, the second not at

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