For the code completion and type hinting in IDEs, just add static typing for the Person and Address classes and you are already good to go. Assuming you use the latest python3.6, here’s a rough equivalent of the typescript classes from your example: # spam.py from typing import Optional, Sequence class Address: street: str housenumber: … Read more
I figured out the answer on my own. I searched, but found no documentation for the 3 type parameters of Generator in the official typing documentation for Python 3.5.2 – beyond a truly cryptic mention of… class typing.Generator(Iterator[T_co], Generic[T_co, T_contra, V_co]) Luckily, the original PEP484 (that started all this) was far more helpful: “The return … Read more
Whenever I’m not 100% sure what types a function accepts, I like to consult typeshed, which is the canonical repository of type hints for Python. Mypy directly bundles and uses typeshed to help it perform its typechecking, for example. We can find the stubs for contextlib here: https://github.com/python/typeshed/blob/master/stdlib/contextlib.pyi if sys.version_info >= (3, 2): class GeneratorContextManager(ContextManager[_T], … Read more
Use float only, as int is implied in that type: def my_func(number: float): PEP 484 Type Hints specifically states that: Rather than requiring that users write import numbers and then use numbers.Float etc., this PEP proposes a straightforward shortcut that is almost as effective: when an argument is annotated as having type float, an argument … Read more
The two concepts aren’t related any more than any other type-related concepts. In short, a TypeVar is a variable you can use in type signatures so you can refer to the same unspecified type more than once, while a NewType is used to tell the type checker that some values should be treated as their … Read more
We can annotate variable-length homogeneous tuples using the … literal (aka Ellipsis) like this: def process_tuple(t: Tuple[str, …]): … or for Python3.9+ def process_tuple(t: tuple[str, …]): … After that, the errors should go away. From the docs: To specify a variable-length tuple of homogeneous type, use literal ellipsis, e.g. Tuple[int, …]. A plain Tuple is … Read more
You can ignore type errors with # type: ignore as of version 0.2 (see issue #500, Ignore specific lines): PEP 484 uses # type: ignore for ignoring type errors on particular lines … Also, using # type: ignore close to the top of a file [skips] checking that file altogether. Source: mypy#500. See also the … Read more
As @jonrsharpe noted in a comment, this can be done with typing.Callable: from typing import Callable def my_function(func: Callable): Note: Callable on its own is equivalent to Callable[…, Any]. Such a Callable takes any number and type of arguments (…) and returns a value of any type (Any). If this is too unconstrained, one may … Read more