KeyError Traceback（最近一次调用最后一次）~\\anaconda3\\lib\\site-packages\\pandas\\core\\indexes\\base.py in get_loc(self, key, method, tolerance)

Question

我正在尝试来自 kaggle 的房价数据集。 我试图清除名为“Alley”的列中的 NaN 值

for column in missing_data.columns.values.tolist():
    print(column)
    print(missing_data[column].value_counts())
    print("")

Id
False    1460
Name: Id, dtype: int64

MSSubClass
False    1460
Name: MSSubClass, dtype: int64

MSZoning
False    1460
Name: MSZoning, dtype: int64

LotFrontage
False    1201
True      259
Name: LotFrontage, dtype: int64

LotArea
False    1460
Name: LotArea, dtype: int64

Street
False    1460
Name: Street, dtype: int64

Alley
True     1369
False      91
Name: Alley, dtype: int64

LotShape
False    1460
Name: LotShape, dtype: int64

LandContour
False    1460
Name: LandContour, dtype: int64

Utilities
False    1460
Name: Utilities, dtype: int64

LotConfig
False    1460
Name: LotConfig, dtype: int64

这些是我在运行上述代码时得到的一些值。 我用它的平均值替换了 LotFrontage 的 NaN 值，并想用它的频率替换“Alley”中的 NaN 值。 但是当我写这段代码时，我得到了一个错误。

train['Alley'].value_counts()

KeyError                                  Traceback (most recent call last)
~\anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2645             try:
-> 2646                 return self._engine.get_loc(key)
   2647             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: 'Alley'

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
<ipython-input-72-8e1e57b44782> in <module>
      1 #replace nan values in Alley with frequency
----> 2 train['Alley'].value_counts()

~\anaconda3\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
   2798             if self.columns.nlevels > 1:
   2799                 return self._getitem_multilevel(key)
-> 2800             indexer = self.columns.get_loc(key)
   2801             if is_integer(indexer):
   2802                 indexer = [indexer]

~\anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2646                 return self._engine.get_loc(key)
   2647             except KeyError:
-> 2648                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   2649         indexer = self.get_indexer([key], method=method, tolerance=tolerance)
   2650         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: 'Alley'

为什么我收到这个错误？ 当名为 Alley 的列存在时？

Answer 1

似乎您可能为数据帧分配了不同的值，因此在下一次迭代中它会抛出错误，因为数据帧可能已分配给熊猫系列