title: Remove NA values in R
body: <p>How can I remove rows which include NA values in a subset of columns?</p>
  
  <p>For the following data.frame, I want to remove rows which have NA in both columns ID1 and ID2:</p>
  
  <pre><code>name  ID1   ID2
  a     NA    NA
  b     NA    2
  c     3     NA
  </code></pre>
  
  <p>I want to receive this one:</p>
  
  <pre><code>name  ID1   ID2
  b     NA    2
  c     3     NA
  </code></pre>