title: Trying to trim 500 columns that has many needing dummy variables-R
body: <p>I've got a data set with 500 columns and many of them will require dummy variables to avoid linearity (ie: income levels that add up to 100%).  I'm trying to develop a regression model. I'm wondering if there is a way to avoid manually going through the columns and adding dummies?  Any thoughts would be appreciated.  I'm trying to determine the 20 or so variables that are significant.
  Thanks</p>