I am using Python3 and have just learned how to use mypy. I was reading the documentation (espcially this part seemed relevant), but couldn't find any answers to my question:
Is is possible to define some shortcuts for types?
Example:
Rather than writing
from typing import List
def f(x: List[int]) -> List[int]:
return x[1:]
I would like to have
from typing import List
sequence = DefineTypeShortcut(List[int])
def f(x: sequence) -> sequence:
return x[1:]
Just to clarify, I do not want to define a new class Sequence, I just want more easily readable signatures of functions.
Yes, you're looking for type aliases. Fortunately they are pretty straight forward, by assigning to a new name the name can act as a hint for the type.
The example supplied in the docs provides an example of exactly the thing you're after:
from typing import List
Vector = List[float]
def scale(scalar: float, vector: Vector) -> Vector:
return [scalar * num for num in vector]