I am using the [`OneHotEncoder`](http://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.OneHotEncoder.html) from Scikit-learn in my project. And I need to know what would be the size of each one-hot vector when the `n_value` is set to be `auto`. I thought `n_value_` would show that but it seems I have no way other than trying out training samples. I made this toy example code to show the problem. Do you know any other solution?

```
from sklearn.preprocessing import OneHotEncoder

data = [[1], [3], [5]] # 3 different features

encoder = OneHotEncoder()
encoder.fit(data)

print(len(encoder.transform([data[0]]).toarray()[0])) # 3 number of dimensions in one-hot-vector
print(encoder.n_values_) # [6] == len(range(5))

```