title: Selecting non-adjacent columns by column number pandas
body: <p>I have yet to find an answer for this anywhere. I am attempting to select columns number <code>2</code> and <code>86:100</code>. Obviously, I would rather not select them by label.</p>
  
  <p>Intuitively I have tried: <code>df_new = df.iloc[:,[2,86:100]]</code> to no avail.</p>
  
  <p>What is the most efficient way of selecting these columns?</p>