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using DataFrame.resample with 'agg' method on non-existant columns provides unexpected behavior #19552

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Merged
merged 1 commit into from
Feb 7, 2018
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using DataFrame.resample with 'agg' method on non-existant columns provides unexpected behavior #19552

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1 change: 1 addition & 0 deletions doc/source/whatsnew/v0.23.0.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -647,6 +647,7 @@ Groupby/Resample/Rolling
- Bug in :func:`DataFrame.groupby` where aggregation by ``first``/``last``/``min``/``max`` was causing timestamps to lose precision (:issue:`19526`)
- Bug in :func:`DataFrame.transform` where particular aggregation functions were being incorrectly cast to match the dtype(s) of the grouped data (:issue:`19200`)
- Bug in :func:`DataFrame.groupby` passing the `on=` kwarg, and subsequently using ``.apply()`` (:issue:`17813`)
- Bug in :func:`DataFrame.resample().aggregate` not raising a `ValueError` when aggregating a non-existent column (:issue:`16766`)

Sparse
^^^^^^
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4 changes: 4 additions & 0 deletions pandas/core/base.py
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Expand Up @@ -392,6 +392,10 @@ def nested_renaming_depr(level=4):

elif isinstance(obj, ABCSeries):
nested_renaming_depr()
elif isinstance(obj, ABCDataFrame) and \
k not in obj.columns:
raise ValueError(
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actuallly I think this should be a KeyError. can you do another PR to fix?

"Column '{col}' does not exist!".format(col=k))

arg = new_arg

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18 changes: 16 additions & 2 deletions pandas/tests/test_resample.py
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Expand Up @@ -20,7 +20,6 @@

from pandas.core.dtypes.generic import ABCSeries, ABCDataFrame
from pandas.compat import range, lrange, zip, product, OrderedDict
from pandas.core.base import SpecificationError
from pandas.errors import UnsupportedFunctionCall
from pandas.core.groupby import DataError
import pandas.core.common as com
Expand Down Expand Up @@ -614,7 +613,7 @@ def f():
t[['A']].agg({'A': ['sum', 'std'],
'B': ['mean', 'std']})

pytest.raises(SpecificationError, f)
pytest.raises(ValueError, f)

def test_agg_nested_dicts(self):

Expand Down Expand Up @@ -659,6 +658,21 @@ def f():
'B': {'rb': ['mean', 'std']}})
assert_frame_equal(result, expected, check_like=True)

def test_try_aggregate_non_existing_column(self):
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I'm not sure that this test is needed because test_agg_misc test covers this case. I added it to show reviewer that original issue is addressed. Let me know and I'll remove this new test.

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Good to keep it.

# GH 16766
data = [
{'dt': datetime(2017, 6, 1, 0), 'x': 1.0, 'y': 2.0},
{'dt': datetime(2017, 6, 1, 1), 'x': 2.0, 'y': 2.0},
{'dt': datetime(2017, 6, 1, 2), 'x': 3.0, 'y': 1.5}
]
df = DataFrame(data).set_index('dt')

# Error as we don't have 'z' column
with pytest.raises(ValueError):
df.resample('30T').agg({'x': ['mean'],
'y': ['median'],
'z': ['sum']})

def test_selection_api_validation(self):
# GH 13500
index = date_range(datetime(2005, 1, 1),
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