AttributeError: 'Ridge' object has no attribute 'coef_

这个错误通常是因为在使用Ridge模型之前没有调用fit()方法进行训练。请确保在调用Ridge模型的coef_属性之前，已经使用fit()方法对模型进行了训练。以下是一个使用岭回归模型的例子，其中包括了对模型的训练和对coef_属性的调用：

from sklearn.linear_model import Ridge
import sklearn.datasets as datasets
from sklearn.model_selection import train_test_split

house = datasets.load_boston()
feature = house['data'][:,4:10] # 选取6列模型
target = house['target']

X_train, X_test, y_train, y_test = train_test_split(feature, target, test_size=0.3, random_state=0)

r = Ridge(alpha=1) # alpha数值越大，正则化力度越大
r.fit(X_train, y_train)

print(r.coef_) # 输出：[-0.063, 0.055, -0.007, -0.819, 0.364, -0.012]