title: convert character to date *quickly* in R
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/12786335/why-is-as-date-slow-on-a-character-vector">Why is as.Date slow on a character vector?</a>  </p>
  </blockquote>
  
  
  
  <p>I have a large <code>data.frame</code> (roughly 60 mil observations) that I read from a database using <code>RMySQL</code>. The dates are brought in as characters (there doesn't seem to be a way to change this) and so I use <code>as.Date</code> to convert things to date.  However, this takes an extremely long time witih so many observations.  Is there anything one can do to make this faster?</p>