Blog Archives

Googling errors

February 14, 2014
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Googling errors

@roguelynn tweeted the other day: If attendees of this weekend’s intro to python workshop leave with one thing, it’ll be to Google your error messages first and foremost. I had just talked about the technique in my Tools for Reproducible Research course, and I had a few recent examples. Gtk-WARNING **: cannot open display: I

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knitr in a knutshell tutorial

February 6, 2014
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knitr in a knutshell tutorial

I spent a lot of time this week writing a short tutorial on knitr: knitr in a knutshell. This is my third little tutorial. (The previous ones were a git/github guide and a minimal make tutorial.) I’m pleased with these tutorials. In learning new computing skills, it can be hard to get started. My goal

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“[” and “[[” with the apply() functions

August 20, 2013
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“[” and “[[” with the apply() functions

Did you know you can use "

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Electronic lab notebook

August 20, 2013
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Electronic lab notebook

I was interested to read C. Titus Brown‘s recent post, “Is version control an electronic lab notebook?” I think version control is really important, and I think all computational scientists should have something equivalent to a lab notebook. But I think of version control as serving needs orthogonal to those served by a lab notebook.

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Read the source code

August 6, 2013
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Read the source code

The other day, there was a bit of a twitter conversation about qqline in R. It made me think: how exactly is the line produced by qqline chosen? I seemed to recall that the line was through the first and third quartiles. An advantage of R is that you can just type the name of

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More on Chutes & Ladders

May 20, 2013
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More on Chutes & Ladders

Matt Maenner asked about the sawtooth pattern in the figure in my last post on Chutes & Ladders. Damn you, Matt! I thought I was done with this. Don’t feed my obsession. My response was that if the game ends early, it’s even more likely that it’ll be the kid who went first who won.

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Chutes & ladders: How long is this going to take?

May 17, 2013
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Chutes & ladders: How long is this going to take?

I was playing Chutes & Ladders with my four-year-old daughter yesterday, and I thought, “How long is this going to take?” I saw an interesting mathematical analysis of the game a few years ago, but it seems to be offline, though you can read it via the wayback machine. But that didn’t answer my specific

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Stack Exchange: Why I dropped out

May 13, 2013
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Stack Exchange: Why I dropped out

Stack Exchange is a series of question-and-answer sites, including Stack Overflow for programming and Cross Validated for statistics. I was introduced to these sites at a short talk by Barry Rowlingson at the 2011 UseR! meeting, “Why R-help must die!“ These sites have a lot of advantages over R-help: The format is easier to read,

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Tutorials on git/github and GNU make

May 10, 2013
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Tutorials on git/github and GNU make

If you’re not using version control, you should be. Learn git. If you’re not on github, you should be. That’s real open source. To help some colleagues get started with git and github, I wrote a minimal tutorial. There are lots of git and github resources available, but I thought I’d give just the bare

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Beware of grep with a list

April 2, 2013
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Beware of grep with a list

Another R tip: beware of as.character applied to a list. Really, beware of grep with a list: You might have thought that the result would be just 1, but grep expects a vector of character strings. If the input is not that, it uses as.character(). Since the result of that starts with "c(", grep finds

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