Oftentimes, it happens I need to calculate the difference of something between two periods. If each row represents a period, the fastest thing to do is to lag the variable you need to perform calculations on. In R, the lag() function from the stats package is an option, but you’ll…
Sometimes I create reports or analyses that I would like to run on a monthly base. It saves some time if I can simply let the report run, without you having to edit any variables. Lubridate has two really cool functions to get the first day or the last day…
In this blog post, I describe to ways to deal with code you do not want to run when it is sourced from an external file in R. When Python sources code it does a particular thing, it assigns the string ‘__main__’ to the __name__ variable in that code. However,…
Recently I had to read in a folder full of large Excel (.xlsx) files. I did as I usually did and use the xlsx library. However, reading in the largest files produced an error: “Error in .jcall(“RJavaTools”, “Ljava/lang/Object;”, “invokeMethod”, cl, : java.lang.OutOfMemoryError: Java heap space” I don’t know what cause…
It happened too many times before I write this blog post. Oftentimes, when I read Excel (xls or xlsx) files into R, I encounter this strange phenomenon where dates are converted to a 5 number integer. Here is how to fix it. For example, 02/01/2017 (dd/MM/yyyy) would be converted to…
Something that took me a while to do properly in ggplot2 is adding the percentage sign as a suffix to your tick labels, controlling decimals and at the same time still being able to set the limits of your axis. I’ll show an example using the iris data set. Let’s…
Although every statistics book will tell you not to go looking for statistical significance, sadly that’s still what happens in many analyses and scientific research. Often forgotten, is to check for statistical power. Here’s a refresher, and how to do it in R. Remember statistical significance? A finding is statistically…
Als de leden van de partijen akkoord gaan, dan schiet de Vlaamse Regering woensdag uit de blokken. Het inburgeringsbeleid wordt strenger gemaakt: Jambon-I maakt het moeilijk, of quasi-onmogelijk, voor internationale migranten om aanspraak te kunnen doen op een sociale woning, de eerste tien jaar van hun verblijf in Vlaanderen. Daarmee…
A two-sample t-test (aka an independent t-test or student’s t-test) is most often used to compare the means of two samples. For example: you might be checking if black cats, on average, have the same body weight as white cats. In this blog post I explain how to do a…
Scientific notation can be handy if you want to save digits. However, if you need to present your results to the board, there’s gonna be that one guy who will ask what the ‘e’-thingy stands for. Here’s how you can make sure that your results are not returned in scientific…