title: R convert factor into numeric
body: <p>How can I change this to numeric values, the number refers to the record of the 1.5km running, containing min:sec:one-tenth of seconds</p>
  
  <pre><code>"4:04.86"  -&gt; 4:04.86
  </code></pre>
  
  <p>as.numeric function is not working in this case, I think, its because of ':'</p>