Python 中可变嵌套 Dict 的类型提示 [英] Type hints for variably-nested Dict in Python
问题描述
因为我在 Python 中经常使用类型提示，所以我遇到了这样一种情况:递归函数接受 dict，以 str 作为键和 int 或 dict 作为值 (Dict[str, Union[int, Dict[...]]).此时的问题是可能的 dict-value 也有 str 作为键和 int 或 dict 作为值 (Dict[str, Union[int, Dict[Dict[str, Union[int, Dict[...]]]]]).
Since I'm working a lot with type hints in Python I came across the scenario that a recursive function accepts dict, with str as keys and int or dict as value (Dict[str, Union[int, Dict[...]]). The problem at this point is that the possible dict-value has also str as keys and int or dict as value (Dict[str, Union[int, Dict[Dict[str, Union[int, Dict[...]]]]).
但是，我不知道传递的字典有什么深度.是否有可能通过类型提示将这种重复模式可视化?
However, I don't know which depth the passed dictionary has. Is there any possibility to visualize this repetitive pattern with type hints?
推荐答案
向往的语法类似于:
RecursiveDict = Dict[str, Union['RecursiveDict', int]]
截至目前，MyPy 不支持此语法 — 错误报告要求支持递归类型已经开放了 6 年.但是，一些替代类型检查器 最近引入了对递归注释的支持.所以，这有点好坏参半.
As of now, MyPy doesn't support this syntax — the bug report asking for support for recursive types has been open for 6 years. However, some alternative type-checkers have recently introduced support for recursive annotations. So, it's a bit of a mixed bag.
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