属性错误：使用 functools.singledispatch 时'function'对象没有属性'register'

Question

目标:创建一个单调度泛型函数;根据functools文档

我想用my_func()来计算dtypes:int或list，成对。

注意:我已经选择实现类型提示，并为我自己的测试用例提出错误，超出了本文的范围。

对于许多参数数据类型提示;这篇文章使用了许多@my_func.register(...)装饰器。

代码:

from functools import singledispatch
from typeguard import typechecked
from typing import Union

@singledispatch
@typechecked
def my_func(x, y):
raise NotImplementedError(f'{type(x)} and or {type(y)} are not supported.')

@my_func.register(int)
def my_func(x: int, y: int) -> Union[int, str]:
try:
return round(100 * x / (x + y))
except (ZeroDivisionError, TypeError, AssertionError) as e:
return f'{e}'

@my_func.register(list)
def my_func(x: list, y: list) -> Union[int, str]:
try:
return round(100 * sum(x) / (sum(x) + sum(y)))
except (ZeroDivisionError, TypeError, AssertionError) as e:
return f'{e}'

a = my_func(1, 2)
print(a)
b = my_func([0, 1], [2, 3])
print(b)

(venv) me@ubuntu-pcs:~/PycharmProjects/project$ python3 foo/bar.py 
/home/me/miniconda3/envs/venv/lib/python3.9/site-packages/typeguard/__init__.py:1016: UserWarning: no type annotations present -- not typechecking __main__.my_func
warn('no type annotations present -- not typechecking {}'.format(function_name(func)))
Traceback (most recent call last):
File "/home/me/PycharmProjects/project/foo/bar.py", line 22, in <module>
@my_func.register(list)
AttributeError: 'function' object has no attribute 'register'

Answer 1

函数必须唯一命名

感谢@Bijay Regmi指出这一点。

@typechecked只在@my_func.register的多态函数之上;不高于@singledispatch功能。

注意:你仍然调用my_func();我只是在测试多态函数。

from functools import singledispatch
from typeguard import typechecked
from typing import Union

@singledispatch
def my_func(x, y):
raise NotImplementedError(f'{type(x)} and or {type(y)} are not supported.')

@my_func.register(int)
@typechecked
def my_func_int(x: int, y: int) -> Union[int, str]:
try:
return round(100 * x / (x + y))
except (ZeroDivisionError, TypeError, AssertionError) as e:
return f'{e}'

@my_func.register(list)
@typechecked
def my_func_list(x: list, y: list) -> Union[int, str]:
try:
return round(100 * sum(x) / (sum(x) + sum(y)))
except (ZeroDivisionError, TypeError, AssertionError) as e:
return f'{e}'

a = my_func_int(1, 2)
print(a)
b = my_func_list([0, 1], [2, 3])
print(b)

(venv) me@ubuntu-pcs:~/PycharmProjects/project$ python3 foo/bar.py 
33
17