title: How to get continuous data to be treated as discrete?
body: <p>I have data on five questions over ten weeks as answered by 150 students. I inputted the data using the student's student #, but now their student numbers are being treated as continuous variables. </p>
  
  <pre><code> Student   Question Type timePeriod week Rating
  1  789331        Q1  SNR        Rt1    1      4
  2  805933        Q1  SNR        Rt1    1      5
  3  826523        Q1  SNR        Rt1    1      4
  4  832929        Q1  SNR        Rt1    1      4
  5  838607        Q1  SNR        Rt1    1      5
  6  841903        Q1  SNR        Rt1    1      2
  </code></pre>
  
  <p>I would like the student numbers to be treated as discrete variables, so I can use them as legend labels when graphing more than one students' response to questions. 
  Is there an easy way to tell R to treat all the numbers in the 'Student' column as labels rather than data? </p>
  
  <p><a href="https://i.stack.imgur.com/GsOhT.png" rel="nofollow noreferrer">What my graph currently looks like</a></p>