ENH: ExtensionArray support for objects with _can_hold_na=False and relational operators #20801
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TomAugspurger
added
the
ExtensionArray
One issue here is for |
| * _formatting_values | ||
| * _can_hold_na | ||
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| Some methods require casting the ExtensionArray to an ndarray of Python |
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No, I reordered _formatting_values and _can_hold_na, since one is a method and the other is an attribute.
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I meant this section specifically. This block is repeated starting on line 57. Or perhaps I'm missing something.
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This is really weird. The copy on my machine is clean and fine, but the copy on GitHub has the repeat. Maybe because I resolved conflicts with master using GitHub interface. UGH.
| # type: () -> bool | ||
| """Whether your array can hold missing values. True by default. | ||
| _can_hold_na = True | ||
| """Whether your array can hold missing values. True by default. |
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Not sure what our recommended style is here. You can probably just change it to a comment.
| @@ -82,8 +82,9 @@ def test_getitem_scalar(self, data): | |||
| assert isinstance(result, data.dtype.type) | |||
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| def test_getitem_scalar_na(self, data_missing, na_cmp, na_value): | |||
| result = data_missing[0] | |||
| assert na_cmp(result, na_value) | |||
| if data_missing._can_hold_na: | |||
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All these changes are a bit unfortunate...
Could we instead have the data_missing fixture raise pytest.skip when necessary? I suspect this would have to be done by the EA author in their code.
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I could make that change to avoid any tests where data_missing is used, and the EA author would have to make that change if they wanted _can_hold_na=False.
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| @pytest.fixture | ||
| def data_missing_for_sorting(): |
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Ah, I clearly didn't have arrays that don't support NA in mind when I wrote this :)
Could you add this note to the data_missing_for_sorting docstring (in tests/extensions/conftest.py).?
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this won't be for 0.23, you are basically defining the ops protocol for abstraction, which is needed, but also needs substantial testing in the current EA classes. |
Yeah, I think I agree given the deadline we set (RC was supposed to be yesterday). I could see this taking a bit of time to get right. @Dr-Irv could you split the changes for |
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@TomAugspurger Yes, I can split the changes out for the |
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Yeah, that'd be nice.
It can be a very simple example I think... Maybe make a subclass of
`DecimalArray` with `_can_hold_na=False` and see if the tests pass once you
apply your changes?
…On Tue, Apr 24, 2018 at 10:09 AM, Dr. Irv ***@***.***> wrote:
@TomAugspurger <https://github.com/TomAugspurger> Yes, I can split the
changes out for the _can_hold_na part. And I see that the operator stuff
I tried to do is part of a bigger discussion. Should I create a new test
case for the _can_hold_na part?
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<#20801 (comment)>,
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closes #20659
closes #20761
git diff upstream/master -u -- "*.py" | flake8 --diffNOTE: I expect that the pandas main developers will object to a lot of what is done here! So let's be open on the discussion.
Goals of this pull request:
ExtensionArray, allow the relational operators to delegate to the base typeExtensionArraytests to handle the cases of_can_hold_na==Falseas best as possible.RelObjectArraythat consists of objects that have operators such as__le__defined that return objects, andaandbareSeriescontaining that type of array, thena <= breturns aSeriesof objects rather than booleans.Things I'm unsure of:
inspectto determine whether the user has implemented the relational operators for the subclassedExtensionArraytype as well as for the base type of elements in the array. I'm not sure if this is best practice or not.__eq__) return objects as opposed to booleans, and some (intentionally) throw exceptions. So I tried to catch these various cases. Not having__lt__defined means that sorting is undefined, and not having__eq__return a boolean messes up some things related togroupby. For my application, that is OK.