Monthly Archives: December 2009

SAS and R included on R bloggers

December 18, 2009
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SAS and R included on R bloggers

The R bloggers site is an aggregator for blogs about R. We're excited to be joining that community and suggest any readers of this blog may also find it useful.

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Visualizing Data with R and ggplot2 (video w/ slides)

December 18, 2009
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On December 3, 2009 I presented a brief talk at the NYC R meetup on how to create data visualizations with R using the immensely powerful ggplot2 package. The talk is very light on motivation but heavy on examples, so it may be more useful to those with some R and/or ggplot2 experience.

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Joining data frames in R

December 17, 2009
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Joining data frames in R

Want to join two R data frames on a common key? Here's one way do a SQL database style join operation in R.We start with a data frame describing probes on a microarray. The key is the probe_id and the rest of the information describes the location on t...

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Image Compression with the SVD in R

December 17, 2009
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Image Compression with the SVD in R

Over the next few posts, I’m going to be reviewing the use of R to implement the most commonly used matrix techniques for image manipulation. The code will be surprisingly simple to understand, because the real magic behind these techniques lies in the mathematics that R provides an abstract interface to. To start, I’m going

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R Blogs

December 17, 2009
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There are many blogs on Statistics, R and other related topics scattered around the internet. The R bloggers website provides a central hub where feeds from participating blogs are collated so that they can be viewed from a single website. This resources certainly appears to be a good idea so that people can more easily identify

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Why use plyr?

December 17, 2009
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The "apply" family of functions in R (apply, sapply, lapply) is a very powerful suite of tools for iterating through structures of data and returning the combined results of each iteration. But with great power comes great responsibility (or something like that): these functions can sometimes be frustratingly difficult to get working exactly as you intended, especially for newcomers...

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Data Profiling in R

December 17, 2009
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Data Profiling in R

In 2006 UserR conference Jim Porzak gave a presentation on data profiling with R. He showed how to draw summary panels of the data using a combination of grid and base graphics. Unfortunately the code has not (yet) been released as a package, so when I recently needed to quickly review several datasets at the

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Matrix Algebra in R: Resources, Videos, Textbooks

December 17, 2009
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Matrix Algebra in R: Resources, Videos, Textbooks

I noticed how John Myles White has posted a useful overview of Matrix Algebra in R. This post lists a couple of other resources that are available on the Internet on the topic, including R resources, online video courses, and online textbooks.Matrix Al...

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Quick Review of Matrix Algebra in R

December 16, 2009
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Lately, I’ve been running a series of fMRI experiments on visual perception. In the interests of understanding the underlying properties of the images I’m using as stimuli, I’ve been trying to learn more about the matrix transformations commonly used for image compression and image manipulation. Thankfully, R provides simple-to-use implementations for all of the matrix

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According to Microsoft, the fourth paradigm of science is data

December 16, 2009
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In scientific discovery, the first three paradigms were experimental, theoretical and (more recently) computational science. A new book of essays published by Microsoft (and available for free download -- kudos, MS!) argues that a fourth paradigm of scientific discovery is at hand: the analysis of massive data sets. The book is dedicated to the late Microsoft researcher Dr Jim...

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