Monthly Archives: August 2014

Revolution Analytics’ User Group Map Contest has a Winner

August 21, 2014
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by Joseph Rickert We are pleased to announce that Jo-fai Chow is the winner of the Revolution Analytics contest. Jo-fai’s entry, which was implemented as a Shiny project, may be viewed by clicking on the figure below. Jo-fai’s work not only produced an aesthetically pleasing sequence of maps but also provides a superb example of a well-documented, small project...

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Extracting Latent Variables from Rating Scales: Factor Analysis vs. Nonnegative Matrix Factorization

August 21, 2014
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Extracting Latent Variables from Rating Scales: Factor Analysis vs. Nonnegative Matrix Factorization

For many of us, factor analysis provides a gateway to learning how to run and interpret nonnegative matrix factorization (NMF). This post will analyze a set of ratings on a 218 item adjective checklist using both principal axis factor analysis and NMF....

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Optimizing with R expressions

August 21, 2014
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Optimizing with R expressions

I recently discovered a powerful use for R expression()’sSay you are trying to fit some experimental data to the following nonlinear equation: Ky0eu(x−tl)K+y0(eu∗(x−tl)−1)+b1+(b0−b1)e−kx+b2x with the independent variable x using nlminb() as the minimization optimizer.This sort of work is significantly improved (i.e. faster with better convergence) if an analytical gradient vector and a Hessian matrix for the objective function are provided....

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For Loop Tracking (Windows Progress Bar)

For Loop Tracking (Windows Progress Bar)

I know that many people consider for-loops the devil, but every so often I get lazy and I use them in the office.  Sometimes it’s nice to keep track of how far through the loop R has gone.  A couple years … Continue reading →

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googleVis!!!

August 20, 2014
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googleVis!!!

I'm back working on R&graphics at last. I've made some progress on the shiny+rgl front, but haven't really had the time to create anything which could be posted here... However, it's been a while, so today I thought I'd take advantage of the releas...

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Open iTerm (OS X) to a Directory from R

August 20, 2014
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Sometimes you need to get to a command prompt from R, whether it’s to wrangle git on the command line or do some package work. RStudio provides ways to do this from menus and hotkeys, but on OS X it sticks you in Terminal.app. I’m an iTerm user—and, I really prefer being in that app vs the one...

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How to integrate R with your calendar

August 20, 2014
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How to integrate R with your calendar

Hilary Parker has contributed a lovely article to Significance, the magazine of the American Statistical Association and the Royal Statistical Society, on using R to set your Google calendar to mark the time of sunsets. Hilary details the process in the article, but the basic idea is to use the sunrise.set function from the StreamMetabolism package to calculate sunset...

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Do your "data janitor work" like a boss with dplyr

August 20, 2014
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Do your "data janitor work" like a boss with dplyr

Data “janitor-work” The New York Times recently ran a piece on wrangling and cleaning data: “For Big-Data Scientists, ‘Janitor Work’ Is Key Hurdle to Insights” Whether you call it “janitor-work,” wrangling/munging, cleaning/cleansing/scrubbing, tidying, or something else, the article above is worth a read (even though it implicitly denigrates the important work that your housekeeping staff does). It’s...

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R Passes SPSS in Scholarly Use, Stata Growing Rapidly

August 19, 2014
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R Passes SPSS in Scholarly Use, Stata Growing Rapidly

by Robert A. Muenchen Here is my latest update to The Popularity of Data Analysis Software. To save you the trouble of reading all 25 pages of that article, the new section is below. The two most interesting nuggets it contains are: … Continue reading →

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dplyr: A gamechanger for data manipulation in R

August 19, 2014
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I demonstrate how to use dplyr for data manipulation in R (R code and data on GitHub ). I had heard of the package before and finally gave it a try after attending Hadley Wickham's presentation at useR! in LA a couple of months ago. dplyr will change y...

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