title: How to filter a data frame
body: <p>I have a data frame and tried to select only the observations I'm interested in by this:</p>
  
  <pre><code>data[data["Var1"]&gt;10]
  </code></pre>
  
  <p>Unfortunately, this command destroys the <code>data.frame</code> structure and returns a long <code>vector</code>.</p>
  
  <p>What I want to get is the <code>data.frame</code> shortened by the observations that don't match my criteria.</p>