BUG: Raise KeyError when indexing a Series with MultiIndex

[ryanreh99]

• closes Wrong "Too many indexers" error message when indexing a Series with MultiIndex #14885
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

[pep8speaks]

Hello @ryanreh99! 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 2019-04-24 14:32:03 UTC

[codecov]

Codecov Report

Merging #26155 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #26155      +/-   ##
==========================================
- Coverage      92%   91.98%   -0.02%     
==========================================
  Files         175      175              
  Lines       52371    52378       +7     
==========================================
- Hits        48184    48182       -2     
- Misses       4187     4196       +9

Flag	Coverage Δ
#multiple	90.54% <100%> (-0.01%)	⬇️
#single	40.74% <0%> (-0.15%)	⬇️

Impacted Files	Coverage Δ
pandas/core/indexing.py	90.56% <100%> (-0.32%)	⬇️
pandas/io/gbq.py	75% <0%> (-12.5%)	⬇️
pandas/core/frame.py	96.9% <0%> (-0.12%)	⬇️
pandas/core/indexes/base.py	96.94% <0%> (-0.06%)	⬇️

---

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[codecov]

Codecov Report

Merging #26155 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #26155      +/-   ##
==========================================
- Coverage   91.98%   91.97%   -0.02%     
==========================================
  Files         175      175              
  Lines       52371    52375       +4     
==========================================
- Hits        48175    48171       -4     
- Misses       4196     4204       +8

Flag	Coverage Δ
#multiple	90.52% <100%> (-0.01%)	⬇️
#single	40.7% <0%> (-0.16%)	⬇️

Impacted Files	Coverage Δ
pandas/core/indexing.py	90.53% <100%> (-0.35%)	⬇️
pandas/io/gbq.py	78.94% <0%> (-10.53%)	⬇️
pandas/core/computation/engines.py	88.33% <0%> (-0.2%)	⬇️
pandas/core/frame.py	96.9% <0%> (-0.12%)	⬇️
pandas/core/indexes/base.py	96.94% <0%> (-0.06%)	⬇️
pandas/core/algorithms.py	94.8% <0%> (+0.01%)	⬆️
pandas/util/testing.py	90.71% <0%> (+0.1%)	⬆️

---

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[jreback]

you additions make this way more complicated, see if you can simplify

[jreback]

pls add a whatsnew note in bug fixes; indexing section. the code change looks good.

[jreback]

small comments, ping on green.

[ryanreh99]

hello @jreback ping

[jreback]

use double backticks on KeyError; use :class:`MultiIndex` ; maybe something more like

Bug in :meth:DataFrame.loc and :meth:Series.loc where KeyError was not raised for a MultiIndex when the key was longer that the number of levels in the :class:MUutiIndex. (:issue:14885).

[ryanreh99]

@jreback actually when key is longer than the levels of the multiindex IndexingError: Too many indexers was raised and is still raised. So would this be more proper?

Bug in :meth:`DataFrame.loc` and :meth:`Series.loc` where ``KeyError`` was not raised for a ``MultiIndex`` when the key was less than or equal to the number of levels in the :class:`MultiIndex` (:issue:`14885`).

[ryanreh99]

made a change to the if statement as a KeyError wasn't raised for a particular condition. Added that test.

[jreback]

thanks @ryanreh99 very nice

[ryanreh99]

@jreback thanks for all the help :D