title: If Statements in R, with a Data Frame
body: <p>Suppose  I have a data frame with several lines that look like:</p>
  
  <pre><code>        User    Lab    Score
           A       1       5
           A       2       6
           A       4       7
           B       1       3
           B       3       4
           C       2       5
  </code></pre>
  
  <p>Then, for lab 1, I want to divide the score by 5, for lab 2, I want to divide the score by 8, for lab 3, I want to divide the score by 7, and for lab 4 I want to divide the score by 9.
  How would I go about doing that? </p>