Blog Archives

Comparison of plots using Stata, R base, R lattice, and R ggplot2, Part I: Histograms

September 21, 2009
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One of the nicer things about many statistics packages is the extremely granular control you get over your graphical output.  But I lack the patience to set dozens of command line flags in R, and I'd rather not power the computer by pumping the mouse trying to set all the clicky-box options in Stata's graphics editor.  I want something...

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R clinic this week: Regression Modeling Strategies in R

September 16, 2009
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At this week's R clinic Frank Harrell will unveil the new rms (Regression Modeling Strategies) package that is a replacement for the R Design package.  He will demonstrate the differences with Design, especially related to enhanced graphics for displaying effects in regression models.  Frank will also discuss the implementation of quantile regression in rms.  The rms package website has...

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Find the function you’re looking for in R

September 14, 2009
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Any R user no matter what level of experience has had trouble finding the package or the function to do what you want to do and then figuring out how to use it.  The sos package in R just made that a lot easier. First, fire up R, then install the sos package (don't omit the quotes): install.packages("sos") It'll ask you to...

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Machine Learning in R

September 10, 2009
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Revolutions blog recently posted a link to R code by Joshua Reich with self-contained examples of using machine learning techniques in R, including various clustering methods (k-means, nearest neighbor, and kernel), recursive partitioning (CART), principle components analysis, linear discriminant analysis, and support vector machines.  This post also links to some slides that go over the basics

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ClipPath copies filename and path from windows for loading into R

September 4, 2009
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I wish I would have discovered this long ago.  Loading data into R or MySQL requires you to specify the full path to the file.  If you do this on a Windows machine there are two annoyances.  First, if you save something to your desktop the path to your desktop is really long.  Second, windows by default uses backslashes...

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ggplot2: more wicked-cool plots in R

July 20, 2009
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As far as I know there are 3 different systems for producing figures in R: (1) base graphics, included with R, (2) the lattice package, and (3) ggplot2, one of the newer plotting systems which is, according to the creator Hadley Wickham, "based on the grammar of graphics, which tries to take the good parts of base and lattice...

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Getting help with R

July 2, 2009
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There's no doubt that by now you've noticed that we're big fans of R around here. It's completely free, has superior graphing capabilities, and with all the extension packages available there isn't much it can't do. One of the problems with R especially to new users is that it isn't obvious how to find help when you...

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Weekly R Clinic

June 24, 2009
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For readers at Vanderbilt: At yesterday's R course I found out that Theresa Scott in the Biostatistics department holds a weekly R clinic and encourages new R users who want to learn more to bring any questions about R, or even your own code and data. The R clinic is held weekly on Thursday from 2:00-3:00 in MCN....

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PDF tutorial from R course (Introduction to R)

June 23, 2009
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Writing from the previously mentioned intro to R course at the Kennedy Center. If you couldn't make it you can download all the course materials from Theresa Scott's website, under the "Current Teaching Material" heading. Here is a direct link to the PDF for the overview materials that we're going over today, along with the R code...

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NYT: In Simulation Work, the Demand Is Real

June 16, 2009
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The New York Times published this interesting article on how the ability to design and perform computer simulations is a highly marketable skill for careers across many disciplines.In methodology development we use simulation nearly every day. We've developed our own specialized genetic data simulation software, genomeSIMLA, that's freely available here by request for PC, Mac, and Linux.But if...

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