Whait what, Excel? You call yourself a data engineer and you work with Excel? Sure. Excel is still the best tool for quick’n’dirty solutions, don’t let Tableau, Python or Alteryx tell you something different… ;)

What’s LAMBDA?

One sentence: LAMBDA allows you to combine common Excel functions into one new custom function (respectively formula) that is available all over your workbook. Back in the days you had to cope with VBA or multiple columns to implement special calculations. LAMBDA still does not cover one disadvantage: Building custom functions remains a mess and ends up with long, encapsulated formulas.

Creating a LAMBDA function…

Let me show you my Python boilerplate and some little nifty standard features I’m working with. You can download the full template from github. This post will probably be extended in the future.

Virtual environment

I like working with virtual environments. It helps me to work with individual clean development environments. How do you do that? Switch to your main development folder, create a subfolder for your new project and initiate it:

cd /development/
mkdir project1
python3 -m venv project1
cd project1
source bin/activate

There you go. If you install packages, they are located in this folder only. Wait, packages? …

Das Internet. Unendliche Weiten. Wir schreiben das Jahr 2020. Das Internet hat eine beachtliche Menge populärer Dienste groß gemacht: E-Mail. Video-Streaming. Vernetzte Kühlschränke. Smart-TV. Und allen voran das World Wide Web, kurz WWW oder auch das Web — für die meisten wohl der Star des Internets.

Online Marketing hat das Web vielleicht nicht umgebracht, aber mindestens nachhaltig geprägt. Doch der Song von The Buggles heißt nun mal nicht Video hat den Radio-Star nachhaltig geprägt…


„Ich bin zu der Einsicht gelangt, dass Werbung die Ursünde des Web ist“

Ethan Zuckerman, horizont.net

Eins vorweg: Das Web ist nicht das Internet, das wird oft missverstanden. Das Internet besteht aus vielen Computern, die miteinander vernetzt sind. Das Web besteht aus Webseiten, die miteinander vernetzt sind und über das Internet übertragen werden.

Das Web feiert bald seinen 30. Geburtstag und Werbung ist seit jeher ein treuer Begleiter und vielleicht auch ein…

Tableau’s drill down feature hits a limit when you want to explore data with multiple dimensions with a high cardinality. I want to show you a way to make browsing tree structures in Tableau more comfortable.

Comparison of drill down mechanics in Tableau and Excel

Lets compare how you browse a hierarchical tree structure in Tableau and in Excel to clarifiy what we want to achieve. I am using an Excel file with random data in 100,000 rows and thirteen columns containing ten dimensions (strings) and three values (doubles). This is how the data is organized:

Hierarchical organised example data

What is a use case for that? I am working in Online Marketing and we organize campaign data in tree structures, where the top-most level represents the country, then comes the channel (SEO, display, …). Below that we have e.g. the publisher name and so on. The last level…

This is a simple guide that will help you to develop an algorithm in JavaScript to create a maze.


Back in the days I stumbled over this BASIC one-liner which is supposed to create a random maze. I tried to reproduce this with JavaScript (source code). It works pretty well, is fast and pretty compact. But if you look closer you will see, that this will never work as a maze.

Not a maze

It’s just some randome lines with no possible solution. So I asked myself: How difficult could it be to create a maze algorithm.

There are in fact a couple…

Nicky Reinert

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