title: Where is the Rails method that converts data from `datetime_select` into a DateTime object?
body: <p>When I use <code>&lt;%= f.datetime_select :somedate %&gt;</code> in a form, it generates HTML like:</p>
  
  <pre><code>&lt;select id="some_date_1i" name="somedate1(1i)"&gt;  #year
  &lt;select id="some_date_2i" name="somedate1(2i)"&gt;  #month
  &lt;select id="some_date_3i" name="somedate1(3i)"&gt;  #day
  &lt;select id="some_date_4i" name="somedate1(4i)"&gt;  #hour
  &lt;select id="some_date_5i" name="somedate1(5i)"&gt;  #minute
  </code></pre>
  
  <p>When that form is submitted, the <code>somedate1(&lt;n&gt;i)</code> values are received:</p>
  
  <pre><code>{"date1(1i)"=&gt;"2011", "date1(2i)"=&gt;"2", "date1(3i)"=&gt;"21", "date1(4i)"=&gt;"19", "date1(5i)"=&gt;"25"}
  </code></pre>
  
  <p>How can I convert that into a DateTime object?</p>
  
  <p>I could write my own method to do this, but since Rails already is able to do the conversion, I was wondering if I could call that Rails method to do it for me?</p>
  
  <p>I don't know where to look for that method.</p>
  
  <p>I'm ultimately trying to solve "<a href="https://stackoverflow.com/questions/5073688/how-to-handle-date-times-in-post-parameters">How to handle date/times in POST parameters?</a>" and this question is the first step in trying to find a solution to that other problem.</p>