title: Ruby date time in string conversion to date time with milliseconds
body: <p>This is a Ruby question (1.9.1)</p>
  
  <p>I have the following date and time in a string:</p>
  
  <pre><code>29 Sep 2013 12:25:00.367
  </code></pre>
  
  <p>I first want to convert it from string to date and time and then
  add 10 seconds to it and convert it back to the same string format as
  above.</p>
  
  <p>I wrote this code:  </p>
  
  <pre><code>format = "%d %b %Y %H:%M:%S"
  date_time = "29 Sep 2013 22:11:30.195"
  parsed_time = DateTime.strptime(date_time, format)
  puts " new date time is #{parsed_time}"
  </code></pre>
  
  <p>Which outputs:</p>
  
  <pre><code>new date time is 2013-09-29T22:11:30+00:00
  </code></pre>
  
  <p>I did not see "195". I tried <code>format = "%d %b %Y %H:%M:%S.%3N"</code> and this gives:</p>
  
  <pre><code>fileOpTest:34:in `strptime': invalid date (ArgumentError) from fileOpTest:34:in `&lt;main&gt;'
  </code></pre>