PyCharm 类型提示对于嵌套字典不明确

Question

I am getting the below warning from Pycharm while trying to access a nested dict. Here is the code to reproduce the behaviour:

response = dict()
response['id'] = 'abc'
response['data'] = dict()
response['data']['field'] = {'value': 10,
                               'confidence': None,
                               'source': 'raw',
                               }
value = response['data']['field']['value']

While trying to access the "value", Pycharm complains about the following warning: Expected type 'Union[int, slice]', got 'str' instead

Can someone please help me understand this behaviour? Thanks!

Answer 1

Here is what I'm seeing:

Pycharm is only auto typing one or two levels deep. (not sure if there is anything you can do about that part). I also agree (as others have pointed out) that the auto-type hinting doesn't make sense to me either. (likely there is a bug there)

However, when I put in my own type hints I can get the warning to go away. (currently using 2020.1)

response: Dict[str, Union[str, Dict[str, Dict[str, Union[int,str,None]]]]] = dict()

Personally I find that super ugly and hard to read. Depending on how often these dictionaries are repeated I will sometimes write something like this:

T_fieldD = Dict[str, Dict[str, Union[int,str,None]]]
T_respD = Dict[str, Union[str, T_fieldD]]

response: T_respD = dict()