Too long error when accessing invalid DataFrame column

[thomasaarholt]

Code Sample, a copy-pastable example if possible

>>> df = pd.DataFrame([1,2,3], columns=['A'])
>>> A['B'] # Accessing invalid colum B
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
~\Miniconda3\envs\py37\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2896             try:
-> 2897                 return self._engine.get_loc(key)
   2898             except KeyError:

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'B'

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
<ipython-input-25-c3fe2ff63dbf> in <module>
----> 1 df['B']

~\Miniconda3\envs\py37\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
   2993             if self.columns.nlevels > 1:
   2994                 return self._getitem_multilevel(key)
-> 2995             indexer = self.columns.get_loc(key)
   2996             if is_integer(indexer):
   2997                 indexer = [indexer]

~\Miniconda3\envs\py37\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2897                 return self._engine.get_loc(key)
   2898             except KeyError:
-> 2899                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   2900         indexer = self.get_indexer([key], method=method, tolerance=tolerance)
   2901         if indexer.ndim > 1 or indexer.size > 1:

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'B'

Problem description

This error is extremely long and makes it hard to debug a very simple error when the code is part of a larger block of code.

Expected Output

KeyError: 'DataFrame' object has no column 'B'
# And ideally, if `df.name` exists and in this case is set to "myframe:
KeyError: 'DataFrame' 'myframe' has no column 'B' # or something similar

Output of pd.show_versions()

INSTALLED VERSIONS

commit : None
python : 3.7.3.final.0
python-bits : 64
OS : Windows
OS-release : 10
machine : AMD64
processor : Intel64 Family 6 Model 94 Stepping 3, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : None.None

pandas : 0.25.3
numpy : 1.16.4
pytz : 2019.1
dateutil : 2.8.0
pip : 19.1.1
setuptools : 41.0.1
Cython : None
pytest : 5.1.2
hypothesis : None
sphinx : 2.2.0
blosc : 1.8.1
feather : None
xlsxwriter : None
lxml.etree : 4.4.1
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 2.10.1
IPython : 7.6.1
pandas_datareader: None
bs4 : 4.7.1
bottleneck : None
fastparquet : None
gcsfs : None
lxml.etree : 4.4.1
matplotlib : 3.1.1
numexpr : 2.6.9
odfpy : None
openpyxl : 2.6.2
pandas_gbq : None
pyarrow : None
pytables : None
s3fs : None
scipy : 1.3.1
sqlalchemy : None
tables : None
xarray : None
xlrd : None
xlwt : None
xlsxwriter : None

[simonjayhawkins]

Thanks @thomasaarholt for the report. I think this is covered by #25996 so closing and marking as duplicate.

[thomasaarholt]

Gotcha. I tried searching first, but I missed the "verbose" keyword and didn't find it at first. Might be worth labelling #25996 as a good first issue?

[simonjayhawkins]

Might be worth labelling #25996 as a good first issue?

probably needs more discussion/agreement before a PR is raised. I'll mark it as needs discussion though.