To edit or add columns to a data.frame, you can use mutate from the dplyr package: [crayon-560298f852be0735619416/] Here, dplyr uses non-standard evaluation in finding the contents for mpg and wt, knowing that it needs to look in the context of… See more › [Read more...]

When trying to parse a large amount of datetime characters into POSXIct objects, it struck me that strftime and as.POSIXct where actually quite slow. When using the parsing functions from lubridate, these where a lot faster. The following benchmark shows… See more › [Read more...]

I was asked to write a R course for a group of innovative companies in the North of the Netherlands. The group of 12 people was a mix of engineers and programmers, and the course aimed at giving them a… See more › [Read more...]

In the course of this year, Dr. Luis Torgo will teach a Data Mining with R course together with the DIKW Academy in Nieuwegein, The Netherlands. Dr. Torgo is an Associate Professor at the department of Computer Science at the… See more › [Read more...]

As with any programming language, R allows you to tackle the same problem in many different ways or styles. These styles differ both in the amount of code, readability, and speed. In this post I want to illustrate this by… See more › [Read more...]

Together with many other packages written by Hadley Wickham, plyr is a package that I use a lot for data processing. The syntax is clean, and it works great for breaking down larger data.frame‘s into smaller summaries. The greatest disadvantage… See more › [Read more...]

In the past few months I have written posts about implementing the bubble sort algorithm in different languages. In the mean while I have gotten some feedback and suggestions regarding improvements to the implementation I made, see the end of… See more › [Read more...]

Parallel processing has become much more important over the years as multi-core processors have become common place. From version 02.14 onwards, parallel processing has become part of the standard R installation in the form of the parallel package. This package… See more › [Read more...]

I had heard the name of the new technical computing language Julia buzzing around for some time already. Now during Christmas I had some time on my hands, and implemented the bubble sort algorithm that I have already posted about… See more › [Read more...]

Recently I wrote a blogpost showing the implementation of a simple bubble sort algorithm in pure R code. The downside of that implementation was that is was awfully slow. And by slow, I mean really slow, as in “a 100… See more › [Read more...]

Please note that this is programming I purely did for the learning experience. The pure R bubble sort implemented in this post is veeeeery slow for two reasons: Interpreted code with lots of iteration is very slow. Bubble sort is… See more › [Read more...]

When text data is in a nice CSV format, read.csv is enough to parse it into a useable format. But if this is not the case, getting the data into a useable format is not so straightforward. In this post… See more › [Read more...]

In case of continuously collected data, e.g. observations from a monitoring network, spatial interpolation of this data cannot be done manually. Instead, the interpolation should be done automatically. To achieve this goal, I developed the automap package. automap builds on… See more › [Read more...]

From the 25th of march onwards, Dr. Luis Torgo will teach a Data Mining with R course together with the DIKW Academy in Nieuwegein, The Netherlands. Dr. Torgo is an Associate Professor at the department of Computer Science at the… See more › [Read more...]

To estimate if a certain vector of numbers will fit into memory, you can quite easily predict the memory usage based on the size of the vector. An integer vector will use 4 bytes per number, and a numeric vector… See more › [Read more...]

To apply a data transformation on an axis in a ggplot, you can use coordinate transformations. For more detail see the ggplot2 documentation. A number of coordinate transformations is available, including log10 and sqrt. However, if you want to perform… See more › [Read more...]

A question on StackOverflow really sparked my attention. The aim was to clean up a dataset of inappropriately spaced words. For example: [crayon-51c87e2141ce8762175339/] My approach was to create what I call a wordpair object. The word pair object for the… See more › [Read more...]

Manually combining R code and a presentation can be quite a pain. Luckily, using tools like odfWeave, Sweave and knitr, integrating documents and R code is quite painless. In this post I want to take a look at combining the… See more › [Read more...]

In part 2 of this series of posts on RStudio Server, I commented that I suspected that RStudio Server would be fast. The first time I tried this from a remote connection, I was disappointed with the performance. Many companies… See more › [Read more...]

After playing around with R studio server for a while, I decided to write a followup to my previous blog post. I want to go over a few of the strong points of using RStudio server to access a remote… See more › [Read more...]