title: R : Column operation on a data frame
body: <p>I have a column in my data frame <code>df</code> called <code>Ratio</code> which comprises of two positive integers <code>x</code> and <code>y</code> separated by a <code>/</code> [That is, format the is <code>x/y</code>]. I would like to replace each row in this column by <code>integer((x/y)*10)</code> (rounded off to the nearest integer)</p>
  
  <p>Example, if that value of an element in <code>Ratio</code> is <code>14/20</code> I need to change it to <code>7</code>.</p>
  
  <p>[There is a level <code>0/0</code> in the <code>Ratio</code> column in which case I would like it changed to <code>5</code>]</p>