BUG: Handle NA values for ExtensionArrays in Series.count

[ghost]

• closes BUG: Series.Count() miscounts NA values in ExtensionArrays #26835
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

[pep8speaks]

Hello @pilkibun! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2019-06-18 00:59:02 UTC

[codecov]

Codecov Report

Merging #26836 into master will increase coverage by 1.4%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master   #26836     +/-   ##
=========================================
+ Coverage   90.45%   91.86%   +1.4%     
=========================================
  Files         179      179             
  Lines       50706    50706             
=========================================
+ Hits        45866    46579    +713     
+ Misses       4840     4127    -713

Flag	Coverage Δ
#multiple	90.45% <100%> (ø)	⬆️
#single	41.1% <100%> (?)

Impacted Files	Coverage Δ
pandas/core/series.py	93.64% <100%> (ø)	⬆️
pandas/core/arrays/categorical.py	95.92% <0%> (+0.12%)	⬆️
pandas/core/indexes/datetimes.py	96.37% <0%> (+0.16%)	⬆️
pandas/core/dtypes/missing.py	93.93% <0%> (+0.6%)	⬆️
pandas/io/formats/printing.py	85.56% <0%> (+1.06%)	⬆️
pandas/io/clipboard/clipboards.py	34.78% <0%> (+2.89%)	⬆️
pandas/core/computation/expr.py	97.8% <0%> (+3.02%)	⬆️
pandas/core/computation/common.py	89.47% <0%> (+5.26%)	⬆️
pandas/io/pytables.py	90.29% <0%> (+26.47%)	⬆️
pandas/core/computation/pytables.py	90.24% <0%> (+27.74%)	⬆️

---

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[codecov]

Codecov Report

Merging #26836 into master will decrease coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #26836      +/-   ##
==========================================
- Coverage   91.86%   91.86%   -0.01%     
==========================================
  Files         179      180       +1     
  Lines       50700    50712      +12     
==========================================
+ Hits        46576    46586      +10     
- Misses       4124     4126       +2

Flag	Coverage Δ
#multiple	90.45% <100%> (ø)	⬆️
#single	41.1% <100%> (-0.08%)	⬇️

Impacted Files	Coverage Δ
pandas/core/series.py	93.64% <100%> (ø)	⬆️
pandas/io/gbq.py	88.88% <0%> (-11.12%)	⬇️
pandas/io/formats/printing.py	85.56% <0%> (-0.54%)	⬇️
pandas/core/frame.py	96.88% <0%> (-0.12%)	⬇️
pandas/util/testing.py	90.84% <0%> (-0.11%)	⬇️
pandas/core/arrays/datetimelike.py	97.92% <0%> (-0.01%)	⬇️
pandas/core/internals/managers.py	95.21% <0%> (-0.01%)	⬇️
pandas/core/internals/blocks.py	94.38% <0%> (-0.01%)	⬇️
pandas/core/arrays/datetimes.py	97.79% <0%> (-0.01%)	⬇️
pandas/core/dtypes/base.py	100% <0%> (ø)	⬆️
... and 22 more

---

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[TomAugspurger]

BaseMethodsTets.test_count seems to only exercise DataFrame.count. Is this bug Series-only?

…

On Thu, Jun 13, 2019 at 2:14 PM pilkibun ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In pandas/tests/extension/decimal/test_decimal.py <#26836 (comment)>: > @@ -380,6 +380,16 @@ def test_divmod_array(reverse, expected_div, expected_mod): tm.assert_extension_array_equal(mod, expected_mod) +def test_na_count(): hmm. Why doesn't BaseMethodsTests.test_count catch this bug then? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#26836?email_source=notifications&email_token=AAKAOIWZW646MUAEJ4ID543P2KL7VA5CNFSM4HX4UUN2YY3PNVWWK3TUL52HS4DFWFIHK3DMKJSXC5LFON2FEZLWNFSXPKTDN5WW2ZLOORPWSZGOB3P5ZXQ#discussion_r293536635>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAKAOIRSWPFSKZYHCO2JKBDP2KL7VANCNFSM4HX4UUNQ> .

[ghost]

yeah. more generally It shows there might be lots of bugs still present when frame methods should but don't return the same result as column by column application, due to EA changes.

[ghost]

btw, what's the norm here, force-push or add commits after review?

[TomAugspurger]

Add new commits.

…

On Thu, Jun 13, 2019 at 2:38 PM pilkibun ***@***.***> wrote: btw, what's the norm here, force-push or add commits after review? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#26836?email_source=notifications&email_token=AAKAOIT6S3VAG4O6YH6MEKTP2KO4NA5CNFSM4HX4UUN2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODXUZ7EY#issuecomment-501850003>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAKAOIXU2BCIPD3HRWKBQTDP2KO4NANCNFSM4HX4UUNQ> .

[ghost]

tests pass and I think I addressed all comments. Ready to merge?

[TomAugspurger]

@pilkibun can you make an ExtensionArray section, and move your release note there?

[ghost]

added

[TomAugspurger]

Thanks!