DOC improve OneHotEncoder's docstring
@@ -155,7 +155,8 @@ class OneHotEncoder(_BaseEncoder):
strings, denoting the values taken on by categorical (discrete) features.
The features are encoded using a one-hot (aka 'one-of-K' or 'dummy')
encoding scheme. This creates a binary column for each category and
- returns a sparse matrix or dense array.
+ returns a sparse matrix or dense array (depending on the ``sparse``
+ parameter)
By default, the encoder derives the categories based on the unique values
in each feature. Alternatively, you can also specify the `categories`
