Recent Posts all posts

Closures A closure is a technique for implementing lexically scoped name binding in a language with first-class functions. Pairs This post is triggered by this question and the nice answer by Martijn Pieters. Here is a super short example: def cons(a, b): def pair(f): return f(a, b) return … Read More »

Command Line As a software developer, I work daily many hours on the command line. This article summarizes some tools and tricks to speed up this work. The basics Bash, ZSH, Fish are Linux shells. Oh-my-ZSH is a plugin for ZSH which is AWESOME! Commands Basics cd: Change directory, e.g. cd … Read More »

Recommender Systems I recently became interested in recommender systems. You know, the thing on Amazon that tells you which products you might be interested in. Or the stuff on Spotify that gives you a song you might like. On YouTube the next videos shown. On StumbleUpon, your next stumble. On a news … Read More »

How old am I? Calculating the age of a person in a web service is harder than one might think to get right. Things you must be aware of are: Time zones: The time zone at the client is likely not the same as on your machine. Hence it could be that the person … Read More »

1822direkt Creating a bank account is one of the things you need to do when you're a longer time in a country, but is incredibly difficult if they don't offer enough information online - especially, if you don't speak the language. I had a pretty good experience with N26, let's see how … Read More »

Bugs Every software project which is not absolutely tiny likely has (or had) bugs, but astonishingly I learned very little about bugs during my university studies. So let's summarize a few important things. What are bugs I define a bug like this: A software bug is a fault in software that … Read More »

Education platform Learning is a core part of human development. Children want to understand the world, adults want to improve their lifes and as a society we want advancement. Education still faces serios inequality problems (example). In some cases because educational material is too expensive, in many cases because having a good … Read More »

Usernames Usernames are used for identification in two places in web services: To let people log in and to allow people recognizing each other. In this article I want to share some ideas on usernames. Username vs Display name When I look into my Stackoverflow profile, they have something called "display … Read More »

Regression A while ago, this link pointed to the content which is now in the Forecasting article. Regression is one of the core tasks in machine learning. In this task, you get some input and your target variable is a single floating point number. For example, predicting the price of a … Read More »

Flask and Gunicorn Flask is a Python web framework and Gunicorn is a Python Web Server Gateway Interface (WSGI) HTTP server. Setup Install the requirements: $ pip3 install flask gunicorn Create an exampleproject.py: import random from flask import Flask app = Flask(__name__) random.seed(0) @app.route("/") def hello(): x = random.randint(1 … Read More »