蟒蛇给予"IndexError: single positional indexer is out-of-bounds"

Question

下面是我使用的代码：

#Divide data into train and test
p_dt_train, p_dt_test = train_test_split(p_main_df, test_size=0.2)
#Shape #(3485868, 26)
p_dt_train.shape
p_fit_DT = DecisionTreeRegressor(max_depth=2).fit(p_dt_train.iloc[:,0:26], p_dt_train.iloc[:,26])

---

但是当我运行上面的代码行(又名p_fit_DT(时，会发生以下错误：

IndexError                                Traceback (most recent call last)
<ipython-input-59-9bbf02d21cd5> in <module>()
1 # In[1]:
2 #Decision tree for regression
----> 3 p_fit_DT = DecisionTreeRegressor(max_depth=2).fit(p_dt_train.iloc[:,0:26], p_dt_train.iloc[:,26])
4 
5 #Apply model on test data
D:My_Workanaconda3libsite-packagespandascoreindexing.py in __getitem__(self, key)
1470             except (KeyError, IndexError):
1471                 pass
-> 1472             return self._getitem_tuple(key)
1473         else:
1474             # we by definition only have the 0th axis
D:My_Workanaconda3libsite-packagespandascoreindexing.py in _getitem_tuple(self, tup)
2011     def _getitem_tuple(self, tup):
2012 
-> 2013         self._has_valid_tuple(tup)
2014         try:
2015             return self._getitem_lowerdim(tup)
D:My_Workanaconda3libsite-packagespandascoreindexing.py in _has_valid_tuple(self, key)
220                 raise IndexingError('Too many indexers')
221             try:
--> 222                 self._validate_key(k, i)
223             except ValueError:
224                 raise ValueError("Location based indexing can only have "
D:My_Workanaconda3libsite-packagespandascoreindexing.py in _validate_key(self, key, axis)
1955             return
1956         elif is_integer(key):
-> 1957             self._validate_integer(key, axis)
1958         elif isinstance(key, tuple):
1959             # a tuple should already have been caught by this point
D:My_Workanaconda3libsite-packagespandascoreindexing.py in _validate_integer(self, key, axis)
2007         l = len(ax)
2008         if key >= l or key < -l:
-> 2009             raise IndexError("single positional indexer is out-of-bounds")
2010 
2011     def _getitem_tuple(self, tup):
IndexError: single positional indexer is out-of-bounds

请指导我哪里出错了。 提前谢谢。

Answer 1

如果您的DataFrame形状为(3485868, 26)，则沿轴 1 的索引将从 0 到 25(包括 0 和 25(。所以也许你的意思是要做：

p_fit_DT = 
DecisionTreeRegressor(max_depth=2).fit(p_dt_train.iloc[:,0:25], 
p_dt_train.iloc[:,25])

如果将代码重构为更多步骤，也可能更清晰，例如：

# Initialise instance for Decision Tree Regression
dtr = DecisionTreeRegressor(max_depth=2)
# Get training inputs and outputs as numpy arrays
X_tr, y_tr = p_dt_train.iloc[:, 0:25].values, p_dt_train.iloc[:, 25].values.reshape((-1, 1))
# Fit model using training data
dtr.fit(X_tr, y_tr)