更改这一行:

model = forest.fit(train_fold, train_y)

到:

model = forest.fit(train_fold, train_y.values.ravel())

.values 将给出数组中的值.(形状:(n,1)

.values will give the values in an array. (shape: (n,1)

.ravel 将该数组形状转换为 (n, )

.ravel will convert that array shape to (n, )