title: One-hot encoding in patsy
body: <p>For regressions I usually encode categorical variables using sklearn's <a href="http://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.OneHotEncoder.html" rel="nofollow noreferrer"><code>OneHotEncoder</code></a>.</p>
  
  <p>I am now exploring using patsy but it doesn't appear to offer One-hot encoding: <a href="http://patsy.readthedocs.io/en/latest/categorical-coding.html" rel="nofollow noreferrer">http://patsy.readthedocs.io/en/latest/categorical-coding.html</a></p>
  
  <p>Is it possible to specify One-hot encoding using patsy?</p>