1288 search results for "Excel"

100 Prisoners, 100 lines of code

July 9, 2010
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100 Prisoners, 100 lines of code

In math and economics, there is a long, proud history of placing imaginary prisoners into nasty, complicated scenarios. We have, of course, the classic Prisoner’s Dilemma, as well as 100 prisoners and a light bulb. Add to that list the focus of this post, 100 prisoners and 100 boxes. In this game, the warden places

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Draw a trophic network with n levels

July 6, 2010
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In the last few weeks, I started focusing more on more of trophic systems with three levels or more. I wanted something to visualize the resulting trophic network, so I came up with a little R function called draw.mnet (which stands for draw a multiple-levels network).

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R for Matlab Users

My favorite software is Matlab, but partly because R is free, more and more people & companies choose to use R as a major working language. Nothing wrong with that, I am at the moment changing some of my Kalman Filter Matlab codes to R.One bothering issue is each software has its own...

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Clustergram: visualization and diagnostics for cluster analysis (R code)

June 15, 2010
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Clustergram: visualization and diagnostics for cluster analysis (R code)

About Clustergrams In 2002, Matthias Schonlau published in “The Stata Journal” an article named “The Clustergram: A graph for visualizing hierarchical and . As explained in the abstract: In hierarchical cluster analysis dendrogram graphs are used to visualize how clusters are formed. I propose an alternative graph named “clustergram” to examine how cluster members are assigned to clusters as...

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The Deepwater Horizon, in context

June 11, 2010
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The Deepwater Horizon, in context

The Earth is pretty big. Give or take, it's about 36,000 feet (11km) to the height of a 747 soaring above Everest, and (in pleasing symmetry) about the same distance down the bottom of the Mariana Trench. (Nonetheless, if you shrunk the Earth down to scale, it would still be smoother than a billiard ball.) So I was surprised...

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3 lines of R code to Process a Web Service

June 9, 2010
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3 lines of R code to Process a Web Service

Ruby is well known for its terse syntax and ability to process web services. I prefer JSON (Javascript Object Notation) to XML whenever possible. For example, a script to retrieve a list of World Bank Data takes all of three lines of code (after in...

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Thoughts on Making Data Work

June 9, 2010
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I really enjoyed all four talks at today's online conference, Making Data Work. (Disclosure: Revolution sponsored this conference.) I thought the four speakers together gave a great overview of issues related to the processing, analysis, and visualization of big data. Mike Driscoll started off with a useful categorization for data size. "Small Data" (<10Gb) fits in the memory of...

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PostGIS in Action Book Review

June 8, 2010
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PostGIS in Action Book Review

I was recently asked to review a soon to be published book on PostGIS, a spatial extension to the very popular Postgresql relational database. I was very excited about receiving an early copy of this book, as the authors have provided countless tips, ...

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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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“Programming with Data – a Guide to the S Language” by John Chambers

June 5, 2010
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“Programming with Data – a Guide to the S Language” by John Chambers

Another unashamedly subjective book review - but first a little more about my history as it relates to R...A few years ago, I was doing some systems administration work at an industrial company for whom IT was a cost center. I wanted to illustrate to...

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