I ran my last triathlon for this year a couple of weeks ago, in the beautiful town of Stratford-upon-Avon. The results were online the day after so I decided to have a look at my fellow competitors’ times, which gave … Continue reading → [Read more...]

At first sight, one could think this picture is a scale model of some narrow moutains, like Bryce Canyon… Actually it represents crimes in East London, an cardboard artwork by the Londoner artist Abigail Reynolds, called Mount Fear.  Here is what can be read on the artist’s webpage: The ... [Read more...]

This is a trivial but very useful tip:__ x=data.frame(a=1:4, c=5)__ x a c1 1 52 2 53 3 54 4 5__ x[1,] a c1 1 5__ x[,1][1] 1 2 3 4__ x[,1, drop=F] a1 12 23 34 4where you can see that:to avoid a[, i] become a vector, rather than a... [Read more...]

If you want more info about clustering, I have another post about "Clustering analysis and its implementation in R". Here is the link:  http://onetipperday.blogspot.com/2012/04/clustering-analysis-2.html------------Several R functions in this... [Read more...]

We were talking with one of my colleagues about doing some text analysis—that, by the way, I have never done before—for which the first issue is to get text in R. Not any text, but files that can be accessed … Continue reading → [Read more...]

“Data scientist” is one of the buzzwords in the running for rebranding applied statistics mixed with some computing. David Champagne, over at Revolution Analytics, described the skills for being a data scientist with a Venn Diagram. Just for fun, ... [Read more...]

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I’d like to explore more the capabilities of my statistical packages to get data online and allocate it in memory instead of download each dataset by hand. After all, I found this task is pretty easy, but got me out of bed for one night trying to find the ... [Read more...]

Data mining is not only statistics, even if statistics is the most recognized academic component of it. It also includes data cleaning, machine learning and data visualization. The scarce factor is the ability to understand that data and extract value ... [Read more...]

This is a piece of code I implemented in 2004, which was supposed to be part of an R-package in multivariate testing (to be named, rather creatively, mvttests). Time has flown, I haven’t still got around to implementing the said package, but people keep asking me for the varcomp function, ... [Read more...]

I have just finished reading this book by Bill Bolstad (University of Waikato, New Zealand) which a previous ‘Og post pointed out when it appeared, shortly after our Introducing Monte Carlo Methods with R. My family commented that the cover was nicer than those of my own books, which is ... [Read more...]

This is a piece of code I implemented in 2004, which was supposed to be part of an R-package in multivariate testing (to be named, rather creatively, mvttests). Time has flown, I haven’t still got around to implementing the said package, but people keep asking me for the sphericity.test ... [Read more...]

There are times when we need to write a function that makes changes to a generic data frame that is passed as an argument. Let’s say, for example, that we want to write a function that converts to factor any … Continue reading → [Read more...]

There have been some exciting developments in the Deducer ecosystem over the summer which should go into CRAN release in the next few months. Today I'm going to give a quick sneak peek at an Open Street Map - R connection with accompanying GUI. This post will just show the ... [Read more...]

With respect to multinomial logit model, the performance difference between the two packages are quite large, based on this post. [Read more...]

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In this post I way to share with you some code to use Openstreetmap – maps as a backdrop for a data visualization. We will use the RgoogleMaps-package for R. In the following I will show you how to make this graph. 1. Download the map I wanted to take a closer ... [Read more...]

Once one starts writing more R code the need for consistency increases, as it facilitates managing larger projects and their maintenance. There are several style guides or suggestions for R; for example, Andrew Gelman’s, Hadley Wickham’s, Bioconductor’s and this one. … Continue reading → [Read more...]

If you use R and haven’t discovered Sweave then go and find out about it. It enables R code and plots to be incorporated into a document so the analysis and report can be combined together in a single document. … Continue reading → [Read more...]

The R Bloggers website, maintained by Tal Galili, aggregates blogs (including mine) from many people of the R community. Tal and I have been wondering about how to tight R Bloggers with the gallery, supporting each other's website. To that extent... [Read more...]