If you’ve ever coded an interactive text-based application in Python, then you’ve probably found that you need a reliable way of asking the user for integers as input. It’s not enough simply to display a prompt and then gather keystrokes. You must check that the user’s input really represents an integer. If it doesn’t, then your code must react appropriately—typically by repeating the prompt. In this tutorial, you’ll learn how to create a reusable utility function that’ll guarantee valid integer […]

If you’re doing text or string manipulation in Python, what do you do if your code is too slow? Assuming your algorithm is reasonably efficient, the next step is to try faster alternatives to Python: a compiled extension. Unfortunately, this is harder than it seems. Some options don’t offer an easy path to optimizations, others are actually slower. To see this limitation in action, we’ll consider some alternatives: Pure Python, with the default Python interpreter. Cython. mypyc. Rust. Pure Python, […]

One of the most common tasks that a computer program performs is to display data. The program often displays this information to the program’s user. However, a program also needs to show information to the programmer developing and maintaining it. The information a programmer needs about an object differs from how the program should display the same object for the user, and that’s where .__repr__() vs .__str__() comes in. A Python object has several special methods that provide specific behavior. […]

When you read someone else’s Python code, you frequently see a mysterious line, which always appears at the top of the file, starting with the distinctive shebang (#!) sequence. It looks like a not-so-useful comment, but other than that, it doesn’t resemble anything else you’ve learned about Python, making you wonder what that is and why it’s there. As if that wasn’t enough to confuse you, the shebang line only appears in some Python modules. In this tutorial, you’ll: Learn […]