title: Should a pandas dataframe column be converted in some way before passing it to a scikit learn regressor?
body: <p>I have a pandas dataframe and passing <code>df[list_of_columns]</code> as X and <code>df[[single_column]]</code> as <code>Y</code> to a Random Forest regressor.</p>
  
  <p>What does the following warnning mean and what should be done to resolve it?</p>
  
  <pre><code>DataConversionWarning: A column-vector y was passed when a 1d array was expected. Please change the shape of y to (n_samples, ), for example using ravel().   probas = cfr.fit(trainset_X, trainset_Y).predict(testset_X)
  </code></pre>