title: filtering data frame based on NA on multiple columns
body: <p>I have the following data frame lets call it <code>df</code>, with the following observations:</p>
  
  <pre><code>id   type   company
  1    NA      NA
  2    NA      ADM
  3    North   Alex
  4    South   NA
  NA   North   BDA
  6    NA      CA
  </code></pre>
  
  <p>I want to retain only the records which do not have NA in column "type" and "company".</p>
  
  <pre><code>id   type   company
  3    North   Alex
  NA   North   BDA
  </code></pre>
  
  <p>I tried: </p>
  
  <pre><code> df_non_na &lt;- df[!is.na(df$company) || !is.na(df$type), ]
  </code></pre>
  
  <p>But this did not work. </p>
  
  <p>Thanks in advance</p>