Video: Quantitative Neuroimaging with R

April 11, 2012
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Video: Quantitative Neuroimaging with R

The following video was recorded at Melbourne R Users. A summary of the talk is as follows: Recent advances in medical imaging allow us to routinely acquire highly detailed images of the living human brain. These images can be used … Continue reading →

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Generate artificial DNA or protein sequences in R in a single line of code.

April 11, 2012
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Generate artificial DNA or protein sequences in R in a single line of code.

To generate an artificial DNA sequence of  "n" bases long with a fixed composition bias in just one line of code, just open your R prompt and type:seqX <- sample(c("A","C","G","T"),10000,rep=TRUE,prob=c(0.4,0.1,0.1,0.4))As you see, the alphabet...

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Epic R is Epic <- Beginners command reference card

April 11, 2012
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Epic R is Epic <-  Beginners command reference card

This reference card has been written by Tom Short.Click the image to see the R magic:Thank you for your support Tom.Benjamin

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Quick Hit: which() and match() are not the same

April 11, 2012
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What’s the difference between using which() and match() in R? For me - about 10 hours! Today I was doing some string matching in R. In my experience performing any sort of regex or string manipulation in R is a mistake....

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Big Data, R and HANA: Analyze 200 Million Data Points and Later Visualize Using Google Maps

April 11, 2012
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Big Data, R and HANA: Analyze 200 Million Data Points and Later Visualize Using Google Maps

Technologies: SAP HANA, R, HTML5, D3, Google Maps, JQuery and JSONFor this fun exercise, I analyzed more than 200 million data points using SAP HANA and R and then brought in the aggregated results in HTML5 using D3, JSON and Google Maps APIs.  Th...

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Latex Allergy Cured by knitr

April 11, 2012
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Latex Allergy Cured by knitr

I have always known that at some point I would have to succumb to the power of Latex, but Latex has been uncharacteristically intimidating to me.  I finally found the remedy to my Latex allergy with the amazing and fantastic knitr package from Yih...

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Stop squinting at word clouds in the hope of getting insights

April 11, 2012
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Stop squinting at word clouds in the hope of getting insights

Someone recently asked on twitter about about peoples' preferences for cloud generators in R. I replied that I thought the "null" word cloud generator was best. By this I mean that I think the word cloud is a bad visualization method. Why? Here is one article with a good perspective, but you can search for

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Flying: Boredom and Terror

April 11, 2012
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Flying: Boredom and Terror

Data represents all planes (not just commercial planes) for the United States "There are only two emotions on a plane: boredom and terror." -- Orson Welles, interview to celebrate his 70th birthday, The Times of London, 6 May 1985. ...

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The age of sail, visualized

April 11, 2012
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As anyone who's ever played Civilization knows, the advent of sailboats capable of crossing the oceans leads to an explosion of exploration, commerce and social development. And with the visualization below, you can see that explosion in action: Ben Schmidt used the R language and data recorded in by hand in ship logs to create the animation above. Like...

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PostgreSQL Scalability Analysis Deconstructed

April 11, 2012
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PostgreSQL Scalability Analysis Deconstructed

In 2010, I presented my universal scalability law (USL) at the SURGE conference. I came away with the impression that nobody really understood what I was talking about (quantifying scalability) or, maybe DevOps types thought it was all too hard (math). Since then, however, I've come to find out that people like Baron Schwartz did get it...

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The Euler Method In R

April 11, 2012
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The Euler Method is a very simple method used for numerical solution of initial-value problems. Although there are much better methods in practise, it is a nice intuitive mechanism. The objective is to find a solution to the equation $$ … Continue reading →

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Customising vegan’s ordination plots

April 11, 2012
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Customising vegan’s ordination plots

As a developer on the vegan package for R, one of the most FAQs is how to customise ordination diagrams, usually to colour the sample points according to an external grouping variable. Now, just because we get asked how to … Continue reading →

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RcppArmadillo 0.3.0 is now on CRAN

April 11, 2012
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Conrad Sanderson has released a new major version 3.0.0 of his excellent Armadillo C++ template library for linear algebra. A corresponding new release 0.3.0 of RcppArmadillo is now on CRAN. This follows four pre-releases of Armadillo which we pack...

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Customising vegan’s ordination plots

April 11, 2012
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Customising vegan’s ordination plots

As a developer on the vegan package for R, one of the most FAQs is how to customise ordination diagrams, usually to colour the sample points according to an external grouping variable. Now, just because we get asked how to do this a lot is not really a reflection on the quality of the plot() methods...

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Getting Started with JAGS, rjags, and Bayesian Modelling

April 10, 2012
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This post provides links to various resources on getting started with Bayesian modelling using JAGS and R. It discusses: (1) what is JAGS; (2) why you might want to perform Bayesian modelling using JAGS; (3) how to install JAGS; (4) where to find furth...

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Speed up your R code using a just-in-time (JIT) compiler

April 10, 2012
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This post is about speeding up your R code using the JIT (just in time) compilation capabilities offered by the new (well, now a year old) {compiler} package. Specifically, dealing with the practical difference between enableJIT and the cmpfun functions. …Read more »

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Using SNA in Predictive Modeling

April 10, 2012
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Using SNA in Predictive Modeling

In a previous post, I described the basics of social network analysis. I plan to extend that example here with an application in predictive analytics. Let's suppose we have the following network (visualized in R)Suppose we have used the igraph package ...

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R at the Consumer Financial Protection Bureau

April 10, 2012
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The O'Reilly Radar blog has a lengthy and very interesting interview with the lead and deputy CIOs of the Consumer Financial Protection Bureau, the new US government agency devoted to consumer protections in the financial markets. In that interview, they talk about the many open-source tools used in the agency (and the parent Treasury Department): Linux, WordPress, Splunk, Django,...

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Working with strings

April 10, 2012
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R has a lot of string functions, many of them can be found with ls("package:base", pattern="str"). Additionally, there are add-on packages such as stringr, gsubfn and brew that enhance R string processing capabilities. As a statistical language and environment, R has an edge compared to other programming languages when it comes to text mining algorithms or natural language processing....

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How to plot lattice and ggplot2 graphs with FastRWeb

April 10, 2012
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How to plot lattice and ggplot2 graphs with FastRWeb

With print() If you are an advanced R user, you probably know the lattice and the ggplot2 packages. They allow you to plot elegant graphics with less code (Hocking, 2009 and Sueur, 2010). If you know these two packages, you should hardly use plot() for your graphs. If you read my article on FastRWeb, you

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R Source on GitHub

April 10, 2012
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I added R source code v0.49 to v2.15.0 to a GitHub repository: r-source Each release is tagged by version number. This is an easy and accessible way to browse R source and diff with prior version. I couldn’t find a suitable alternative. ...

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An Introduction to Social Network Analysis with R and NetDraw

April 10, 2012
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With the rise in the use of social media, data related to social networks is ripe for analysis using techniques from social network analysis and graph theory. According to International Network for Social Network Analysis, ‘Social network analysis is...

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RcppDE 0.1.1

April 9, 2012
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The RcppDE package required a bug-fix release. One of the tests compared results to those from the DEoptim package this is based upon, and these are no longer equal, leading the tests to fail. While I was at it, I finally committed a few more things t...

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Calling Systematic Investor Toolbox from Excel using RExcel & VBA

April 9, 2012
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Calling Systematic Investor Toolbox from Excel using RExcel & VBA

RExcel is a great tool to connect R and Microsoft Excel. With a press of a button, I can easily execute my R scripts and present output interactively in Excel. This easy integration allows non-R users to explore the power R language. As an example of this approach, I want to show how to create

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Piggybacking and Hopefully Publicizing R Experts

April 9, 2012
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Piggybacking and Hopefully Publicizing R Experts

I was inspired by the Revolution Analytics blog post http://blog.revolutionanalytics.com/2009/11/charting-time-series-as-calendar-heat-maps-in-r.html on the d3.js style calendar heat map that Paul Bleicher from Humedica developed in R.  In an effo...

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Quick off the mark

April 9, 2012
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Quick off the mark

With none of the top teams overimpressing this season, Alan Pardew’s performance with Newcastle – especially in the transfer market -is likely to see him receive coniderable recognition in the Manager of the Year award Recent acquisition, Papiss Cissé, has proved particularly fruitful with a brace against Swansea last time out taking him to nine

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R package ETLUtils @ CRAN – easy loading into ffdf

The R package ETLUtils is now available for download at it's CRAN repository.It's a package which facilitates the ETL in situations where you need to interact with SQL databases in a corporate environment. Basically it currently focusses on t...

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Correlation Matrix (Constituents)

April 9, 2012
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Correlation Matrix (Constituents)

It is important to understand as better as possible our sample set before to develop the regression. Continuing with the “Y” matrix (constituent’s matrix) we have to observe the correlation matrix.In the R Graph Gallery, we can get the code to dr...

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Comparing Julia and R’s Vocabularies

April 9, 2012
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While exploring the Julia manual recently, I realized that it might be helpful to put the basic vocabularies of Julia and R side-by-side for easy comparison. So I took Hadley Wickham’s R Vocabulary section from the book he’s putting together on the devtools wiki, put all of the functions Hadley listed into a CSV file,

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