title: Split string in a column based on character position
body: <p>I have a dataframe like this:</p>
  
  <pre><code>                Basic Stats        Min       Max      Mean     Stdev   
  1        LT50300282010256PAC01   0.336438  0.743478  0.592622  0.052544   
  2        LT50300282009269PAC01   0.313259  0.678561  0.525667  0.048047   
  3        LT50300282008253PAC01   0.374522  0.746828  0.583513  0.055989   
  4        LT50300282007237PAC01  -0.000000  0.749325  0.330068  0.314351   
  5        LT50300282006205PAC01  -0.000000  0.819288  0.600136  0.170060 
  </code></pre>
  
  <p>and for the column <code>Basic Stats</code> I want to retain only the characters between <code>[9:12]</code>  so for row 1 I only want to retain <code>2010</code> and for row 2 I only want to retain <code>2009</code>.  Is there a way to do this?</p>