Type Hinting¶
Overview¶
In the sample functions provided with the template repository, you will see something like:
If you aren't familiar with type-hinting, that's what the : float, : int, and -> NDArray are indicating. They tell the user what the expected types are for each parameter and return. They are not enforced in any way; they are merely hints (as the name suggests). It is always advisable to use type hints in your code, so get in the habit of doing so!
Tip
If you have to import a given function solely for type-hinting purposes, you should put it within an if TYPE_CHECKING block (as demonstrated in /src/template/examples/sample.py). It will then only be imported when using a type-checking utility, reducing the overall import time of your module.
Note
You do not need to touch the py.typed file. It is a marker that Python uses to indicate that type-hinting should be used in any programs that depend on your code.
Type Checking¶
As mentioned, the type hints are just that: hints. If you want to ensure that the types are strictly adhered to across your codebase, you can use mypy to do so. This is a slightly more advanced tool, however, so is not something you need to worry about right now.