title: Iterate through array and remove certain string elements
body: <p>I'm parsing an html page with nokogiri and extracting some data points. It seems to extract the correct data points, but also extracts nulls and comma's, here's a sample of whats extracted :</p>
  
  <pre><code>null,
  3.28,
  null,
  null,
  null,
  1.91,
  2.83,
  null,
  9.06,
  null,
  3.80,
  6.42,
  null,
  </code></pre>
  
  <p>I want to be able to remove all instances of "null," as well as commas in general and then convert each element to a float. The above doesn't seem to be removing "null," at all. </p>