键入一个带有可调用的函数

Question

我有很多具有相同签名的函数，比如(int, int) -> int.

有没有办法用 a Callable（或其他东西）来输入这些函数，以避免为每个函数指定参数类型和返回类型？我想做类似的事情（但显然失败了）：

from typing import Callable

f: Callable[[int, int], int]
def f(x, y):  #  with the previous line, this is equivalent to 'def f(x: int, y: int) -> int:'
    ...

运行 mypy 结果：

file.py:4: error: Name "f" already defined on line 3
Found 1 error in 1 file (checked 1 source file)

Answer 1

也许有更优雅的解决方案。不推荐，但您可以设置<function>.__annotations__。有关它的更多信息请参见此处。

from typing import get_type_hints

callable_int_annotations = {"x": int, "y": int, "return": int}

def f_with_hint(x: int, y: int) -> int:
    return x + y

def f_without_hint(x, y):
    return x + y

print(f"Before {get_type_hints(f_with_hint)=}")
print(f"Before {get_type_hints(f_without_hint)=}")

f_without_hint.__annotations__ = callable_int_annotations

print(f"After {get_type_hints(f_with_hint)=}")
print(f"After {get_type_hints(f_without_hint)=}")

Before get_type_hints(f_with_hint)={'x': <class 'int'>, 'y': <class 'int'>, 'return': <class 'int'>}
Before get_type_hints(f_without_hint)={}
After get_type_hints(f_with_hint)={'x': <class 'int'>, 'y': <class 'int'>, 'return': <class 'int'>}
After get_type_hints(f_without_hint)={'x': <class 'int'>, 'y': <class 'int'>, 'return': <class 'int'>}