title: Removing rows from a dataframe based on a large list
body: <p>I have a long list of values which I want to use as indexing to remove rows from another data frame which contains this values at a specific column.</p>
  
  <p>A simple examle to make it is</p>
  
  <pre><code>X &lt;- data.frame(Variable1=c(11,14,12,15),Variable2=c(2,3,1,4))
  X[X$Variable1!=11 &amp; X$Variable1!=12, ]
  </code></pre>
  
  <p>but is there any efficient way to use the dataframe with the values I have which is the list I want to use in the second dataframe?</p>