title: What's the right way to replicating "having" in data table?
body: <p>I'd like to filter on grouped data with data table</p>
  <p>Let's say my data was this</p>
  <pre><code>library(data.table)
  mtcars[ ,.(cars = n()), .(cyl)]
  </code></pre>
  <p>And let's say that I wanted to only get the groups that have 3 or more cars</p>
  <p>This is one way to do it</p>
  <pre><code>mtcars[ ,.(cars = n()), .(cyl)][cars &gt; 3]
  </code></pre>
  <p>Is that the right way to do it?</p>