I'm transitioning to Python from a Java background, and I'm finding it easy to write new code or read code I just wrote, but I'm struggling with older code. Sometimes I can't remember what types I assigned to variables, which is not an issue in Java where type declarations are explicit. I'm considering whether using type hints is a good practice to avoid confusion. Is there a general consensus on when to apply type hints? Should I use them liberally, or is there a risk of overcrowding my code? Also, I know modern Java has type inference with `var`, but it's rarely used due to version issues. What's the best approach here?
5 Answers
Honestly, in notebooks, type hints aren’t necessary since you have live objects you can inspect using `?`, `help()`, or `dir()`. For larger projects, they’re more useful, especially when using IDEs for linting and auto-completion, but avoid overcomplicating your code just for type hints. If they clutter your code, rethink their usage!
For new code, I always type hint everything, including variables, parameters, and returns. It significantly enhances my editor experience. However, converting old code can be a jungle; it's painful but understanding the nuances helps in the long run.
Type hints are most useful for function parameters and return types, as well as for class attributes. They help clarify what types you are working with, especially when they can't be easily inferred. For example, if you have a function that returns a dictionary of lists, it’s helpful to specify that explicitly.
I agree! Collections often need type hints for better understanding.
Use type hints primarily when needed, especially in ambiguous situations. For the most part, I type hint in new code but don’t stress it too much in older projects.
In my experience, use type hints when they help clarify things for the type checker. If mypy flags a type issue, that’s when I add hints. Otherwise, Python does a good job of inferring types, especially for simple cases. Plus, a good IDE shows you the types when you hover over them, which is super helpful!
That's true for regular scripts, but be cautious in notebooks like Google Colab, which don’t support type checking as well.
Agreed. Type hints just provide clarity where needed, but don’t force them everywhere.
Good point! Remember, static typing doesn’t necessarily mean fewer bugs—automated tests are key.