Posts Tagged ‘ programming ’

A Case Study in Optimising Code in R

February 16, 2010
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A Case Study in Optimising Code in R

This post presents an experience I had optimising the efficiency of code for a data analysis task in R. I'm not an expert in programming nor code optimisation. However, I thought my experience might make an interesting case study for others at a simila...

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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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[, [[, $: R accessors explained

October 21, 2009
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[, [[, $: R accessors explained

For more than ten years, I have been teaching R both formally and informally. One thing that I find often trips up students is the use of R’s accessors and mutators. ( For those readers not from a formal computer science background, an accessor is a method for accessing data in an object

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Compiling and Cross-compiling R packages for Windows (win32)

September 3, 2009
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so recently i’m learning how to compile and cross-compile R packages from source for windows machines, which means i have to create windows binaries. the first option is to build on a windows system, and the 2nd is to cross-build on an intel-based linux or mac system. i will outline my experience. Send it off

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R and data

May 26, 2009
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R and data

My fellow bloggers John and Scott have posted recently about the free statistical programming language R.  How does it compare to an expensive language like SAS? If you’ve done any statistical analysis, then you’ll know that getting and cleaning the data is a major step in any project.  SAS does a pretty good job at

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S3 vs S4, efficiency issues

May 23, 2008
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S3 vs S4, efficiency issues

While developing some new simulation code with S4 system I stumbled upon some big difficulties in terms of computational efficiency. That lead me to diging into archives of Rhelp and Rdevel looking for clues. I found some interesting threads that address almost exactly the same problems that I do. Read for yourself here and here,

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Resources for S4 classes and methods

January 23, 2008
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Resources for S4 classes and methods

Learning the programming in the new S4 system of classes and methods in R can be quite cumbersome, even though the methods package is very well documented. That is why I collected some of the info and materials that I am aware of on a separate page here. I warmly welcome any suggestions for extending

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Documentation and tutorial roundup

June 4, 2007
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Documentation and tutorial roundup

I recently lost my documentation folder (oops), so I had to go online and retrieve the documentation files and tutorials that I find indispensible for working. I decided I’d save myself and everyone else the trouble by posting the list here. All of the files are available in PDF format. All R manuals Scilab documentation.

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