title: Get names of dummy variables created by get_dummies
body: <p>I have a dataframe with a very large number of columns of different types. I want to encode the categorical variables in my dataframe using <code>get_dummies()</code>. The question is: is there a way to get the column headers of the encoded categorical columns created by <code>get_dummies()</code>?</p>
  <p>The hard way to do this would be to extract a list of all categorical variables in the dataframe, then append the different text labels associated to each categorical variable to the corresponding column headers. I wonder if there is an easier way to achieve the same end.</p>