title: Remove rows in dataframe with factor ""
body: <p>I have a dataframe like x where the column genes is a factor. I want to remove all the rows where column genes has nothing. So in table X I want to remove row 4. Is there a way to do this for a large dataframe? </p>
  
  <pre><code>X 
  names   values   genes
  1 A  0.2876113  EEF1A1 
  2 B  0.6681894   GAPDH
  3 C  0.1375420 SLC35E2
  4 D -1.9063386        
  5 E -0.4949905   RPS28
  </code></pre>
  
  <p>Finally result:</p>
  
  <pre><code>X 
  names   values   genes
  1 A  0.2876113  EEF1A1 
  2 B  0.6681894   GAPDH
  3 C  0.1375420 SLC35E2
  5 E -0.4949905   RPS28
  </code></pre>
  
  <p>Thank you all!</p>