title: Incorrect Conversion of Date as a Factor to a Date
body: <p>I am having trouble calculating a date that is imported in from a .csv file.   What I want to do is take that date in the factor DateClosed and generate a date in a date field (a).   Example if a=203 I want the date to be the equivalent of DateClosed-203.   However, I am having trouble with the code listed below. </p>
  
  <p>DateClose is a factor.</p>
  
  <pre><code>&gt; head(DateClosed)
  [1] 7/30/2007  12/12/2007 5/8/2009   6/24/2009  6/24/2009  2/29/2008 
  165 Levels: 1/12/2010 1/15/2011 1/15/2013 1/17/2009 1/18/2008 1/19/2012 1/2/2013 1/21/2013 1/22/2010 1/24/2013 1/26/2014 ... 9/7/2010
  &gt; head(as.Date(DateClosed,format="%m/%d/%y"))
  [1] "2020-07-30" "2020-12-12" "2020-05-08" "2020-06-24" "2020-06-24" "2020-02-29"
  
   head(as.Date(DateClosed,format="%m/%d/%y"))-203
  [1] "2020-01-09" "2020-05-23" "2019-10-18" "2019-12-04" "2019-12-04" "2019-08-10"
  </code></pre>
  
  <p>It subtracts 203 days correctly but for some reason reads the date wrong.  </p>