title: Use of formula in information.gain in R
body: <p>In the function definition for the FSelector information.gain function,</p>
  
  <p><strong>information.gain(formula, data)</strong></p>
  
  <p>what exactly is the purpose of the formula? I'm trying to use the function to do feature selection for a classification task. In the few examples that I've seen online, it seems like the formula defines some kind of relationship between the class label and the features in the dataset. However, if this is the case, I don't know the exact linear relationship between the features and the labels since I'm performing a classification task, so what would the formula be?</p>