To raise or not to raise exceptions, and the art of designing return values
Each time we call a function that’s meant to perform some operation that could succeed or fail we are always left with the same dilemma. …
Learning to rank with Python scikit-learn
If you run an e-commerce website a classical problem is to rank your product offering in the search page in a way that maximises the …
Introducing Hash#dig_and_collect, a useful extension to the Ruby Hash#dig method
In this blog post I will introduce Hash#dig_and_collect , a simple utility method that is built on top of Hash#dig to help you navigate nested hashes mixed …
Dockerized Rails Capybara tests on top of Selenium
If you use Docker to deploy your Rails application you may want to use the same infrastructure to run your tests. However the setup of your Selenium …
How to isolate complex queries in an object oriented fashion
Building complex queries in ruby can make your code quite difficult to read, manage and reuse. In this blog post I’ll present a simple method to …
Create isolated Jupyter ipython kernels with pyenv and virtualenv
Everyone loves isolation. Makes our life easier and our systems much more robust. Isolating Jupyter notebooks makes no exception. Maybe you want to try some cutting …
A/B Testing, from scratch
If you work in a diligent web development business you probably know what an A/B test is. However, its fascinating statistical theory is usually left behind. …
Cross Validation done wrong
Cross validation is an essential tool in statistical learning to estimate the accuracy of your algorithm. Despite its great power it also exposes some fundamental …
Data manipulation primitives in R and Python
Both R and Python are incredibly good tools to manipulate your data and their integration is becoming increasingly important. The latest tool for data manipulation …
Upload video files with progress bar using Rails, Paperclip and Javascript
Rails does not help much when dealing with AJAX uploads by means of external JS libraries. I recently came across a case where a user …