Membership testing means checking if a collection of items (a list, a set, a dictionary, etc.) contains a specific item. For example, checking if a list of even numbers contains number 42. It’s a quite common operation, so let’s see how to do it properly. How can we check if…

How do you check if something is True in Python? There are three ways: One “bad” way: if variable == True: Another “bad” way: if variable is True: And the good way, recommended even in the Programming Recommendations of PEP8: if variable: The “bad” ways are not only frowned upon…

A quick tip: when you write an important command in shell, put a comment next to it so you can easily find it later or remember what it does: pytest -m slow --durations=10 # Run slow tests, return the slowest Why?

Using the latest version of Python is always a good idea. First of all - you get the new features like the f-strings (Python 3.6), ordered dictionaries (officially guaranteed from Python 3.7, but already present in Python 3.6), or the union operator (Python 3.9). But even if you don't use…

Apart from the list comprehension method, in Python, we also have dictionary comprehension — a little less known but very useful feature. It’s a perfect tool for creating a dictionary from an iterable. Let’s see how we can use it and if it’s faster than other methods. The simplest way…

A few months ago, I moved from Evernote to Obsidian. I have been using Evernote for as long as I can remember. And every now and then, I checked some alternative solutions. I tried Notion, but its first version was excruciatingly slow on mobile (waiting for 10+ seconds each time…

There are two different ways to create a dictionary. You can call the dict() function or use the literal syntax: {}. And in many cases, these are equivalent choices, so you might give it little thought and assume they both take the same amount of time. But they don’t! Starting…

While preparing to write the “Writing Faster Python” series, the first problem I faced was: “How do I benchmark a piece of code in an objective yet uncomplicated way?” I could run python -m timeit <piece of code>, which is probably the simplest way of measuring how long it takes…

I’ve decided to skip last year’s Advent of Code edition. Mostly because I didn’t have time, but I also knew that I probably wouldn’t finish it. I’ve never finished any edition. I’m not very good at code katas, and I usually try to brute force them. …