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python - ValueError：未知标签类型：使用 KNN 时为“未知”

问题描述

我是 python 新手并尝试运行 KNN，但是当我输入代码时，我收到错误 ValueError: Unknown label type:'unknown'。我已经对所有分类数据进行了编码，并删除了我不需要的那些，以避免虚拟陷阱。我还需要做什么来清除它？

from sklearn.neighbors import KNeighborsClassifier
from sklearn.metrics import fbeta_score

training_accuracy = []
test_accuracy = []    
neighbors_settings = range(1, 11)

for n_neighbors in neighbors_settings:
     knn = KNeighborsClassifier(n_neighbors=n_neighbors)
     knn.fit(x_train, y_train)
     train_pred=knn.predict(x_train)
     test_pred=knn.predict(x_test)   

training_accuracy.append(fbeta_score(y_train, train_pred, beta=1))
test_accuracy.append(fbeta_score(y_test, test_pred, beta=1))

plt.plot(neighbors_settings, training_accuracy, label="training accuracy")
plt.plot(neighbors_settings, test_accuracy, label="test accuracy")
plt.ylabel("Accuracy")
plt.xlabel("n_neighbors")
plt.legend()
plt.savefig('knn_compare_model')

我希望有一个图表来显示测试和训练的准确性，但我在下面得到了这个；

 ValueError                                Traceback (most recent call last)
<ipython-input-22-8a3a1f3c5c24> in <module>

    11     # build the model    
    12     knn = KNeighborsClassifier(n_neighbors=n_neighbors)     
---> 13     knn.fit(x_train, y_train)
>
    14     
    15     # if accuracy of prediction on training set is high but it is low 
           on test set: So overfitting     

C:\ProgramData\Anaconda3\lib\site-packages\sklearn\neighbors\base.py in fit(self, X, y)
    903             self.outputs_2d_ = True    
    904     
    --> 905         check_classification_targets(y)
    906         self.classes_ = []   
    907         self._y = np.empty(y.shape, dtype=np.int)    
>
C:\ProgramData\Anaconda3\lib\site-packages\sklearn\utils\multiclass.py in 
   check_classification_targets(y)
    169     if y_type not in ['binary', 'multiclass', 'multiclass- multioutput', 
    >
    170                       'multilabel-indicator', 'multilabel-sequences']:    
    --> 171         raise ValueError("Unknown label type: %r" % y_type)
    >
    172    
    173    

ValueError: Unknown label type: 'unknown'

标签： pythonknn

解决方案

您y_train可能是可能导致此错误的对象类型，因此请添加该行

y_train = y_train.astype('int')

前

knn.fit(x_train, y_train)

也对你的y_test.

希望这可以帮助！

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