BUG: dir(IntervalIndex()) raises

In [8]: ix=pd.IntervalIndex.from_breaks([0,1,2])
   ...: dir(ix)
...
ValueError: cannot infer type for <class 'NoneType'>

[jschendel]

Thanks for the report @pilkibun! I can confirm this behavior. Interestingly, dir(pd.IntervalIndex) is fine, it's just a constructed IntervalIndex that fails.

[jbrockmendel]

Looks like in it is calling ix.str and taht calls lib.infer_dtype which raises because its not looking at an ndarray

[vishwakftw]

I'm new to the project, but from a cursory glance of the documentation pd.IntervalIndex.from_breaks only accepts array-likes, and range(3) is not an array-like (based on pd.core.dtypes.inference.is_array_like.

So, isn't range(3) technically an incorrect input?

[TomAugspurger]

@vishwakftw the docs for IntervalIndex.from_breaks should maybe be updated to require "list-like" rather than "array-like". I haven't looked closely.

That said, I think that's separate from the issue @pilkibun reported.