Re-posting this blog from my other blog on Analytics (http://allthingsbusinessanalytics.blogspot.com/)Did Netflix make a bad move or a bold move, only time will tell but for now here is a simple sentiment analysis using R and TwitteR pac... [Read more...]

The 8th international R users conference useR! 2012 will be in Nashville TN USA June 12-15 with a special all-day pre-conference course from Bill Venables on June 11. We have [Read more...]

A while back I wrote a blog post on the R package I wrote for reading and manipulating grads data. The library is quite basic, and does not support a number of grads data file options: Using one ctl file,… See more › [Read more...]

The graduated symbol schematics below have been created in R (using ‘symbols’). They plot combinations of country territorial and population sizes. Instead of dividing for population density we multiply for a function of both. The total of box areas is … Continue reading → [Read more...]

This post shows how to print a prettier nested pivot table, created using the {reshape} package (similar to what you would get with Microsoft Excel), so you could print it either in the R terminal or as a LaTeX table. This task is done by bridging between the cast_df ... [Read more...]

I’ve been writing a fair amount of R recently and have been going through a good learning period, here are some functions that I’ve discovered (mainly plyr and reshape related) and thought I would share: merge_all is a good way to merge multiple different data frames, rather ... [Read more...]

I was a bit annoyed by the error when loading a dataset that contains multi-byte characters. R basically just chokes on them. I have not really understood the intricacies of this, but it was basically just an annoyance and since I did not really use these characters in the strings ... [Read more...]

Previous post presented the problem of dishonest casino that ocassionally uses loaded die. Sequence of the real states is hidden, and we are trying to figure it out just by looking at the observations (symbols). If we apply our implementation … Continue reading → [Read more...]

  Last year, I covered a number of the so-called “Twitter protests” in China (#cn220), Iran (#25bahman), and Algeria (#fev12).  Since these protests began in January 2011, the Arab Spring has claimed many members of both ruling and revolting groups … Continue reading → [Read more...]

The Multiple Factor Model can be used to decompose returns and calculate risk. Following are some examples of the Multiple Factor Models: The expected returns factor model: Commonality In The Determinants Of Expected Stock Returns by R. Haugen, N. Baker (1996) The expected returns factor model: CSFB Quantitative Research, Alpha Factor ... [Read more...]

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Le Monde puzzle of last weekend was about sudoku-like matrices. Consider an (n,n) matrix containing the integers from 1 to n². The matrix is “friendly” if the set of the sums of the rows is equal to the set of the sum of the columns. Find examples for n=4,5,6. Why ... [Read more...]

Example in the mentioned book goes as following – dishonest casino uses two types of dice. Fair one that has equal probability of landing on either side (1/6), and the loaded one with 50% chance for getting 6. Your task … Continue reading → [Read more...]

Often you want to set the fixed colors for particular range of your dataset to be sure that the visual output is correctly represented. This is particularly useful for time series data, where the range or your dataset might drastically … Continue reading → [Read more...]

Sometimes I play with non-linguistic data sets recreationally. It's a totally valid hobby! I tend to gravitate towards data on the disparities between men and women, because gender equality is something that matters to me.I've had this one data set for... [Read more...]

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For fear of being left way behind as Martin Hawksey starts to get to grips with R, (see for example how he’s using R to automate the annotation of Google Spreadsheets with calculations that don’t come readily or efficiently to hand in Google Spreadsheets itself), I thought I ... [Read more...]

Another new local R user group has just started up, this time in Cleveland, OH. The Cleveland R User Group is the brainchild of R user Nicholas Hermez, and their first meeting on February 22 is a get-together to plan future topics, presenters and venues. If you're in the Cleveland area ... [Read more...]

I was having a little trouble getting RStudio to process BibTex entries and compile a LaTeX file. Bumping around on the great RStudio help forum, I found this entry, which pointed me in the direction. I needed to set a system environment variable in R ... [Read more...]