title: Pandas DataFrame RangeIndex
body: <p>I have created a Pandas DataFrame. I need to create a RangeIndex for the DataFrame that corresponds to the frame -
  <code>RangeIndex(start=0, stop=x, step=y)</code> - where <code>x</code> and <code>y</code> relate to my DataFrame.</p>
  
  <p>I've not seen an example of how to do this - is there a method or syntax specific to this?</p>
  
  <p>thanks</p>