在Jupyter Notebook中无法理解由熊猫引起的关键错误

Question

因此，这是代码中存在上述问题的一部分。我认为问题可能是由熊猫更新引起的，导致很久以前一切似乎都工作正常。 TY

阅读课堂成绩

df = pd.read_csv('data/student-mat.csv')

过滤掉0分的成绩

df = df[~df['G3'].isin([0, 1])]

df = df.rename(columns={'G3': 'Grade'})

df.head()
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日志：

KeyError                                  Traceback (most recent call last)
~\Anaconda51\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   3077             try:
-> 3078                 return self._engine.get_loc(key)
   3079             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: 'G3'

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
<ipython-input-4-2948d93a326d> in <module>()
      3 
      4 # Filter out grades that were 0
----> 5 df = df[~df['G3'].isin([0, 1])]
      6 
      7 df = df.rename(columns={'G3': 'Grade'})

~\Anaconda51\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
   2686             return self._getitem_multilevel(key)
   2687         else:
-> 2688             return self._getitem_column(key)
   2689 
   2690     def _getitem_column(self, key):

~\Anaconda51\lib\site-packages\pandas\core\frame.py in _getitem_column(self, key)
   2693         # get column
   2694         if self.columns.is_unique:
-> 2695             return self._get_item_cache(key)
   2696 
   2697         # duplicate columns & possible reduce dimensionality

~\Anaconda51\lib\site-packages\pandas\core\generic.py in _get_item_cache(self, item)
   2487         res = cache.get(item)
   2488         if res is None:
-> 2489             values = self._data.get(item)
   2490             res = self._box_item_values(item, values)
   2491             cache[item] = res

~\Anaconda51\lib\site-packages\pandas\core\internals.py in get(self, item, fastpath)
   4113 
   4114             if not isna(item):
-> 4115                 loc = self.items.get_loc(item)
   4116             else:
   4117                 indexer = np.arange(len(self.items))[isna(self.items)]

~\Anaconda51\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   3078                 return self._engine.get_loc(key)
   3079             except KeyError:
-> 3080                 return self._engine.get_loc(self._maybe_cast_indexer(key))
   3081 
   3082         indexer = self.get_indexer([key], method=method, tolerance=tolerance)

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: 'G3'

Answer 1

第二次执行笔记本时，不再有“ G3”，因为它现在是“ Grade”。

您需要做的是使单元格保持一致，而不是编写它们，以使一个单元格内的代码取决于上一个单元格的状态。

例如，在这种情况下，要从数据集中删除“ G3”的单元格应该是一个单独的单元格，以便您知道在此单元格之后，就不能再使用G3。