title: Matplotlib - labelling points (x,y) on a line with a value z
body: <p>I'm trying to make a 2d plot using pyplot. I'm reading in a file with several columns, each of which contains around 100 values between 1 and 10. I'm plotting column 5 against column 6, which is fine. </p>
  
  <p>What I also want to do is label the resulting line with integer values from column 0. So the line will have 11 points on, at the positions (x,y) where column 0 is an integer. I'd also like those points to be labelled with that integer.</p>
  
  <p>I'd really appreciate any help with this, its driving me crazy!   </p>