Why Today's Python Developers Are Embracing Type Hints

Summary

Python is one of the most successful programming languages out there, with it recently overtaking Javascript as the most popular language on GitHub, according to the latest GitHub Octoverse report. The report emphasises the popularity of the language in the growing fields of AI, data science and scientific computing - fields where speedy experimentation and iteration are critical, and where developers are coming from a broad range of STEM backgrounds, not necessarily computer science. But as the Python community expands and projects grow from experiments to production systems, that same flexibility can become a liability. That’s why today we’re going to talk about typed Python - what it is, why it’s become important for Python developers today, and how to get started using it to write higher quality, more reliable code. What is Typed Python?​ Before we dive into why you should be using typed Python in your daily development lives, first we need to understand some core concepts and how we got here. Dynamic vs static typing​ The classic Python programming language that you know and love is dynamically typed. What does that mean exactly? It means that types are determined at runtime, not when you write your code. Variables can hold any type of value, and you don't need to declare what type they are. Here’s an example of dynamic typing in action: x = 5 x = "hello" x = [1,2,3] This behaviour is one of the things that sets Python apart from languages that are statically typed, like Java or C++, which require you to declare types from the get go: int x = 5;std::string x_str = "hello";std::vector<int> x_vec = {1, 2, 3}; In the above example we can’t just reassign the variable x to a value of whatever type we want, it can only hold an integer because of the static typing nature of the C++ language. The fact that Python is a dynamically typed language is one of the reasons it is so easy to use and popular amongst new and experienced programmers alike. It makes it easy to deve...