我刚开始学习机器学习,并且使用波士顿数据集进行预测。除了 precision_score 和 accuracy_score 的结果外,其他一切都运行正常。我做了以下操作:
import pandas as pd import sklearn from sklearn.linear_model import LinearRegressionfrom sklearn import preprocessing,cross_validation, svmfrom sklearn.datasets import load_bostonimport numpy as npfrom sklearn.metrics import accuracy_score, f1_score, precision_score, recall_score, classification_report, confusion_matrixboston = load_boston()df = pd.DataFrame(boston.data)df.columns= boston.feature_namesdf['Price']= boston.targetX = np.array(df.drop(['Price'],axis=1), dtype=np.float64)X = preprocessing.scale(X)y = np.array(df['Price'], dtype=np.float64)print (len(X[:,6:7]),len(y))X_train,X_test,y_train,y_test=cross_validation.train_test_split(X,y,test_size=0.30)clf =LinearRegression()clf.fit(X_train,y_train)y_predict = clf.predict(X_test)print(y_predict,len(y_predict))print (accuracy_score(y_test, y_predict))print(precision_score(y_test, y_predict,average = 'macro'))
现在我得到了以下错误:
File “LinearRegression.py”, line 33, in
accuracy = accuracy_score(y_test, y_predict) File "/usr/local/lib/python2.7/dist-packages/sklearn/metrics/classification.py",
line 172, in accuracy_score
y_type, y_true, y_pred = _check_targets(y_true, y_pred)
File “/usr/local/lib/python2.7/dist-packages/sklearn/metrics/classification.py”, line 89, in _check_targets
raise ValueError("{0} is not supported".format(y_type)) ValueError: continuous is not supported
回答:
您使用的是线性回归模型,如下所示:
clf = LinearRegression()
它预测的是连续值。例如:1.2, 1.3
而 accuracy_score(y_test, y_predict)
期望的是布尔值。1 或 0(真或假)或分类值,如 1,2,3,4 等。这些数字作为类别使用。
这就是您得到错误的原因。
如何解决这个问题?
由于您试图预测波士顿数据的 Price
,这是一个连续值。我建议您将错误度量从准确度改为 RMSE 或 MSE
替换:
print(accuracy_score(y_test, y_predict))
为:
from sklearn.metrics import mean_squared_errorprint(mean_squared_error(y_test, y_predict))
这将解决您的问题。