title: Parse datetime with lubridate
body: <p>I am trying to parse the following datetime with the following format:</p>
  
  <pre><code>library(lubridate)
  a &lt;- "2004-05-07 18:24:58.666424"
  </code></pre>
  
  <p>I tried the following, but returned NAs</p>
  
  <pre><code>b &lt;- lubridate::mdy_hms(a)
  c &lt;- lubridate::mdy(a)
  </code></pre>
  
  <p>Could anyone please explain how to parse this. I am also fine if lubridate is not used.</p>