A column-vector y was passed when a 1d array was expected

Question

I need to fit RandomForestRegressor from sklearn.ensemble.

forest = ensemble.RandomForestRegressor(**RF_tuned_parameters)
model = fo         


        

Answer 1

I also encountered this situation when I was trying to train a KNN classifier. but it seems that the warning was gone after I changed:
knn.fit(X_train,y_train)
to
knn.fit(X_train, np.ravel(y_train,order='C'))

Ahead of this line I used import numpy as np.