python - 未找到虚拟变量列头？

Question

我正在尝试对一门课程进行逻辑回归，但我遇到了一些非常奇怪的问题，我以前从未见过这个错误。我是一个完整的 python 菜鸟，所以我希望能在细节上非常具体。请为我低调！

这是我的代码：

import pandas as pd
import matplotlib.pyplot as plt
cancer=pd.read_csv('C:\\Users\\kpic1\\Desktop\\Spring 2019\\IDIS 450\\Second exam\\Provided documents\\Cancer_Research_Q2.csv')
cancer.set_index('PatientID', inplace=True)
cancer=pd.get_dummies(cancer, columns=['Class'], drop_first=True)
cancer.head()
from sklearn.model_selection import train_test_split
cancer.rename(columns={'Class_Malignant':'Malignant'}, inplace=True)
cancer.head()

返回的表显示最后仍然命名为“Class_Malignant”的虚拟变量。

当我尝试使用仅打印此列时

print(cancer['Class_Malignant'])

我收到以下长错误：

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
~\Anaconda3\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: 'Class_Malignant'

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
<ipython-input-15-09d1356e98ac> in <module>
      1 #for some reason, "Class_Malignant" is not registering as a column head?
----> 2 print(cancer['Class_Malignant'])

~\Anaconda3\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):

~\Anaconda3\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

~\Anaconda3\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

~\Anaconda3\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)]

~\Anaconda3\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: 'Class_Malignant'

据我所知，数据集中不存在列名“Class_Malignant”？有人知道发生了什么吗？

标签： pythonpandasmatplotlibdummy-variable