title: New column from non-standard date factor in R
body: <p>I have a dataframe with an oddly formatted dates column. I'd like to create a column just showing the year from the original date column and I am having trouble coming up with a way to do this because the current date column is being treated as a factor. Any advice on how to do this efficiently would be appreciated.</p>
  
  <p>Example<br>
  starting with:</p>
  
  <pre><code>org &lt;- c("a","b","c","d")
  country &lt;- c("1","2","3","4")
  date &lt;- c("01-09-14","01-10-07","11-31-99","10-31-12")
  toy &lt;- data.frame(cbind(org,country,date))
  toy
    org country     date
  1   a       1 01-09-14
  2   b       2 01-10-07
  3   c       3 11-31-99
  4   d       4 10-31-12
  
  str(toy$date)
  Factor w/ 4 levels "01-09-14","01-10-07",..: 1 2 4 3
  </code></pre>
  
  <p>Desired result:</p>
  
  <pre><code>  org country     Year
  1   a       1     2014
  2   b       2     2007
  3   c       3     1999
  4   d       4     2012
  </code></pre>