The world is full of linear relationships. When one apple costs $1 and two apples cost $2, it's easy to figure out the price of any number of apples. But what happens when you have 100s of data points? What if your data source is noisy? That's when it's helpful to use a technique called linear regression. In this article Julie Kent shows us how linear regression works, and walks through a practical example in Ruby.

We've all worked with tightly-coupled code. If a butterfly flaps its wings in China, the unit tests break. Maintaining a system like this is...unpleasant. In this article, Jonathan Miles dives into the origins of tight-coupling. He demonstrates how you can use dependency injection (DI) to decouple code. Then he introduces a novel decoupling technique based on delegation that can be useful when DI is not an option.

In today’s post, we’ll look at system tests in Rails 6. System tests are meant to auto-test the way users interact with your application, including the Javascript in your user interface. Minitest, being the default testing framework in Rails, is a great match for system testing. With all the configuration that Rails handles for us, there are just a few steps needed before we have our first tests up and running.

In case you missed it, we released Ruby gem 2.10. It focusses mostly on diagnose and configuration. Though a bit late, here’s a round-up of what’s in the release.

You know Big-O is important - not only for acing your next job interview but for knowing how code works at scale. But have you ever taken the time to go beyond a superficial understanding of the subject? In this article, Julie Kent uses equal parts math and Ruby to reveal the beating heart of Big-O and show us how it ticks.

Have you ever dealt with a unicode bug? Where plain text — the substance you work with all day — can no longer be trusted? It can be disorienting to say the least! This article will help prepare you so that the next time that happens you’ll be able to spend less time hyperventilating and more time troubleshooting.

In this post, we’ll look into tried and true methods of improving Rails view performance. Specifically, I will focus on database efficiency, view manipulation, and caching. I think the phrase “premature optimization is the root of all evil” has been taken a little out of context. I’ve often heard developers use this during code reviews when simple optimization techniques are pointed out.

In today’s post, we’ll cover the significant differences and benefits of using structure.sql versus the default schema.rb schema formats in your Ruby on Rails application. In a data-driven world, knowing how to exploit all of your database’s rich features can make the difference between a successful and unsuccessful enterprise.

Hi there stroopwafel fans As we’re looking forward to publishing more Ruby, Elixir, and JavaScript posts in the coming 2020, we decided to take a look back at the blog posts that you gave the most hearts on Twitter, reads on the blog, and that we got the most appreciation for in 2019.

In this post, we’ll explore how to create Ruby modules that are configurable by users of our code — a pattern that allows gem authors to add more flexibility to their libraries. Most Ruby developers are familiar with using modules to share behavior. After all, this is one of their main use cases, according to the documentation.