使用python机器学习库scikit-learn的RandomForestClassifier代码片段。
我正在尝试使用scikit的RandomForestClassifier中的class_weight opition为不同的类赋予权重.Below是我的代码片段，然后是我得到的错误
print 'Training...'
forest = RandomForestClassifier(n_estimators=500,class_weight= {0:1,1:1,2:1,3:1,4:1,5:1,6:1,7:4})
forest = forest.fit( train_data[0::,1::], train_data[0::,0] )
print 'Predicting...'
output = forest.predict(test_data).astype(int)
predictions_file = open("myfirstforest.csv", "wb")
open_file_object = csv.writer(predictions_file)
open_file_object.writerow(["PassengerId","Survived"])
open_file_object.writerows(zip(ids, output))
predictions_file.close()
print 'Done.'
我收到以下错误：
Training...
IndexError Traceback (most recent call last)
<ipython-input-20-122f2e5a0d3b> in <module>()
84 print 'Training...'
85 forest = RandomForestClassifier(n_estimators=500,class_weight={0:1,1:1,2:1,3:1,4:1,5:1,6:1,7:4})
---> 86 forest = forest.fit( train_data[0::,1::], train_data[0::,0] )
87
88 print 'Predicting...'
/home/rpota/anaconda/lib/python2.7/site-packages/sklearn/ensemble/forest.pyc in fit(self, X, y, sample_weight)
216 self.n_outputs_ = y.shape[1]
217
--> 218 y, expanded_class_weight = self._validate_y_class_weight(y)
219
220 if getattr(y, "dtype", None) != DOUBLE or not y.flags.contiguous:
/home/rpota/anaconda/lib/python2.7/site-packages/sklearn/ensemble/forest.pyc in _validate_y_class_weight(self, y)
433 class_weight = self.class_weight
434 expanded_class_weight = compute_sample_weight(class_weight,
--> 435 y_original)
436
437 return y, expanded_class_weight
/home/rpota/anaconda/lib/python2.7/site-packages/sklearn/utils/class_weight.pyc in compute_sample_weight(class_weight, y, indices)
150 weight_k = compute_class_weight(class_weight_k,
151 classes_full,
--> 152 y_full)
153
154 weight_k = weight_k[np.searchsorted(classes_full, y_full)]
/home/rpota/anaconda/lib/python2.7/site-packages/sklearn/utils/class_weight.pyc in compute_class_weight(class_weight, classes, y)
58 for c in class_weight:
59 i = np.searchsorted(classes, c)
---> 60 if classes[i] != c:
61 raise ValueError("Class label %d not present." % c)
62 else:
IndexError: index 2 is out of bounds for axis 0 with size 2
请帮忙！