Blog Archives

Vertica and R quickie – group_concat transform function

June 23, 2014
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Vertica and R quickie – group_concat transform function

I’m guessing you can do this in C++, but hey… it works for me. You’ll notice 3 functions that need to be created, the main function which will be called from Vertica, the params functions which is optional and holds the config of parameters optionally pased to the function. And finally, and mandatory, is the

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R and Vertica

June 14, 2014
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R and Vertica

I’ve been spending the last few months working my way through the integration of R and Vertica, and will try to keep here things that I find handy. I’m quite sad to see there is not much about this Vertica feature on the web, that’s a little disappointing. But, it didn’t stop us from creating a

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A note about the estimating the number of visits to a site

October 21, 2013
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A note about the estimating the number of visits to a site

Motivation How many times do users visit your site? A very relevant question in web analysis. One major issue that biases your estimation is the users who save no cookies, these users change their ID on every page visit so they look like 1 time visitors and thus inflate the proportion of 1 in the [&hellip

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An example of linear discriminant analysis

January 8, 2011
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An example of linear discriminant analysis

The following example was shown in an advanced statistics seminar held in tel aviv. The material for the presentation comes from C.M Bishop’s book : Pattern Recognition and Machine Learning by Springer(2006). One way of separating 2 categories using linear sub spaces of the input space (e.g. planes for 3D inputs, lines for 2D inputs, [&hellip

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Finding out (fast) the classes of data.frame vectors

August 6, 2010
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Finding out (fast) the classes of data.frame vectors

Sometimes it’s useful to write down the various classes of vectors inside your data.frame objects for documentation and other people to use it. I’ve searched for a quick way to find out all the classes of vectors inside a data.frame. Since I’ve found no reference for such a function/process I made one up. I’d like [&hellip

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Color choosing in R made easy

May 21, 2010
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Color choosing in R made easy

I don’t know about you, but when I want to make a graph in R, I handpick the colors, line widths etc… to produce awesome output. A lot of my time is spent on color choosing, I had to find a more convenient way of doing so. Earl F. Glynn’s “Chart of R colors”  posted [&hellip

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