# Monthly Archives: April 2010

## Social Network Analysis using R and Gephis

April 28, 2010
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After learning the basics of R, I decided to learn something harder last week. I picked Social Network Analysis (SNA) to learn the concepts of SNA and R. My primary interest in SNA is visual exploration of networks, so I needed to find a tool first.&n...

## Transitions in R redux

April 28, 2010
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Previously, I shared with the world a function to create a pairwise matrix of the number of transitions and transversions between two DNA sequences. Klaus Schliep kindly pointed out the possibility of a bug in the function and offered a faster, more accurate version. Thanks Klaus! titv mat res for(i...

## Using R for Introductory Statistics, Chapters 1 and 2

April 27, 2010
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I'm working my way through Using R for Introductory Statistics, by John Verzani, a free version of which is available as SimpleR. Chapter 1 ...covers basics of R such as arithmetic, loading libraries and reading data. We also get an introduction to v...

## How to do this graph using R

April 26, 2010
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I am showing three examples that will help an average R user to create beautiful graphs. The interesting (may be useful) parts of these examples are the use of some very smart but tricky functions to, for example, add a Greek symbol on a plot, add a title to a plot with some mathematical symbols. I am showing three...

## R Project and Google Summer of Code: Welcome to our students!

April 26, 2010
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A few hours ago, I sent the following to both the R development list and the informal R / GSoC list: Date: Mon, 26 Apr 2010 15:27:29 -0500 To: R Development List CC: gsoc-r Subject: R and the Google Summer of Code 2010 -- Please welcome our new st...

## R is going to have a GUI to ggplot2! (by the end of this years google-summer-of-code)

April 26, 2010
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I was delighted to see the following e-mail post from Dirk Eddelbuettel regarding the google-summer-of-code R google group: * * * Earlier today Google finalised student / mentor pairings and allocations for the Google Summer of Code 2010 (GSoC 2010). The R Project is happy to announce that the following students have been accepted: Colin Rundel, “rgeos – an...

## R Project websites down

April 26, 2010
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The main R Project website, www.r-project.org, many of the primary CRAN mirrors (including cran.r-project.org), and r-forge.r-project.org are currently unavailable following a power failure at the master host in Austria. The US CRAN mirror, cran.us.r-project.org, and other mirrors not under the r-project.org domain (including cran.revolution-computing.com) are still accessible. In addition, the following services are not affected: bugs.r-project.org, developer.r-project.org, ess.r-project.org, search.r-project.org,...

## A serial Connection for R

April 26, 2010
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***UPDATED: June 3, 2010 – revert name from “tty” to “serial“, R version (2.11.1)*** I’m working on a patch for R (currently 2.11.1) that adds a serial connection feature for POSIX systems (i.e. Linux, Mac OS X, …). The serial connection works like the other connections. For example, the following code opens, writes a single

## Example 7.34: Propensity scores and causal inference from observational studies

April 26, 2010
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Propensity scores can be used to help make causal interpretation of observational data more plausible, by adjusting for other factors that may responsible for differences between groups. Heuristically, we estimate the probability of exposure, rather t...

## R : NA vs. NULL

April 25, 2010
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The R language has two closely related NULL-like values, NA and NULL ... Both are used to represent missing or undefined values. This has lead to much confusion.