[Python-Dev] Type hinting: TypeError: 'type' object is not subscriptable

[Ivan Levkivskyi]

You should use List[int] (note capital first letter) and similar for other
generic types.
Please read https://docs.python.org/3/library/typing.html

The fact that this is accepted by PyCharm is a PyCharm bug, and should be
reported on their tracker.

--
Ivan



On 29 April 2017 at 14:32, Edward Ned Harvey (python) <python at nedharvey.com>
wrote:

> Years ago, I fell in love with python and left C an C++ behind. Sometime
> later, I fell in love with C# because with strong typing, my IDE does most
> of the work for me - I never have to browse the API to find which method or
> attribute exists in a class, I can use tab completion for everything, avoid
> type-o's, etc. So I was recently thrilled to discover type hinting in
> python, and support included in pycharm. I'm coming back to python now (for
> the last few months).
>
>
>
> In python 3.6.1, and pycharm CE 2017.1.1 on windows (I haven't tested
> other versions or other platforms):
>
>
>
> The following is recognized and supported by pycharm, but then at runtime,
> python throws an exception:
>
>
>
>                 #!/usr/bin/env python3
>
>
>
>                 def foo(bars: list[str]):
>
>                                 for bar in bars:
>
>                                                 if bar.startswith("hi"):
>
>                                                                 raise
> ValueError("bar should never say hi")
>
>                                 return True
>
>
>
>
>
>                 if foo(["a","b","c"]):
>
>                                 print("Ok")
>
>
>
>
>
>                 TypeError: 'type' object is not subscriptable
>
>
>
> The problem is that python doesn't recognize list[str] as a type. Pycharm
> handles it, and everything works fine if I'm using a non-subscripted type,
> like plain old int, or str, or anything else.
>
>
>
> Is this a bug, or is it something python simply hasn't implemented yet, or
> is it something that's not going to be implemented?
>
>
>
> Is there a workaround?
>
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