# Blog Archives

## The guessing game in R (with a twist, of course)

May 27, 2010
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Maybe you remember playing this one as a kid. If you are about my age, you may have even created a version of this game as one of your first computer programs. You guess a number, the computer tells you if you if you are too low or high. I’ve limited the number of maximum

## Zone of instability

May 26, 2010
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I woke up from my afternoon nap feeling a bit off-kilter, so I decided to go for another random walk. In particular, I wanted a journey that avoided the center, but didn’t just run for an exit either. After playing around for a while I came up with this: # Take a wacky walk, return

## How many tanks? MC testing the GTP

May 25, 2010
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$How many tanks? MC testing the GTP$

It’s 1943 and you work for the good guys. A handful of German tanks have been captured, and each one has a serial number. This is back when serial numbers were still presumed to come in serial, one right after the other. Given your collection of numbered tanks, and assuming that any existing tank was

## R: A random walk though OOP land.

May 20, 2010
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If you are used to object oriented programing in a different language, the way R does things can seem a little strange and backwards. “proto” to the rescue. With this library you can simulate “normal” OOP. I found the examples for proto not so helpful, so to figure out how the package works I sent

## R: Dueling normals

May 18, 2010
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More playing around with R. To create the graph above, I sampled 100 times from two different normal distributions, then plotted the ratio of times that the first distribution beat the second one on the y-axis. The second distribution always had a mean of 0, the mean of first distribution went from 0 to 4,

## Connecting R and Python

May 7, 2010
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There are a few ways to do this, but the only one that worked for me was to use Rserve and rconnect. In R, do this: 1 2 3 install.packages("Rserve") library(Rserve) Rserve(debug = FALSE, port=6311, args=NULL) Then you can connect in Python very easily. Here is a test in Python: 1 2 rcmd = pyRserve.rconnect(host='localhost', port=6311) print(rcmd('rnorm(100)'))

## R: choose file dialog box

May 6, 2010
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Needed this one recently, it pops up a window to pick a file to be used by r, then reads the contents into myData: myFile

## Game of Life in R

May 5, 2010
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Before I decided to learn R in a serious way, I thought about learning Flash/Actionscript instead. Most of my work involves evolutionary models that take place over time. I need visual representations of change. It’s certainly possible to represent change and tell an evolving story with a single plot (see for example Tufte’s favorite infographic),

## R: directing output to file on the fly, output flushing

May 4, 2010
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To start sending all output to a file, do this: sink("path/to/filename") # Direct all output to file print("Hi there") # Will be printed to file sink() # Turn off buffing to file Related to this I recently had to use: flush.console() This forces your console to print out any buffered content. Doing this will cost time, but if you are running

## First annual R plot replication prize

May 3, 2010
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\$100 to the first person who can figure out how I created this plot and replicate it. Some hints: It was done in R. There is only one underlying probability distribution involved (one “rdist()“). Including the “plot” statement, I created this with 3 short lines of code. This is based on a random sampling of unstated size, so