title: Inconsistent date formats
body: <p>I'm using R to analyze some data and I have this data set and I'm trying to get a subset of the data that is only using the most current dates. I'm having trouble doing this and some of my dates have different formats. </p>
  
  <p>ex.  10/01/00
       10/01/00
       10/20/2000
       05/13/2000</p>
  
  <p>How can I get these to be all the same format?</p>