title: Categorize numeric variable with mutate
body: <p>I would like to a categorize numeric variable in my <code>data.frame</code> object with the use of <code>dplyr</code> (and have no idea how to do it).</p>
  
  <p>Without <code>dplyr</code>, I would probably do something like:</p>
  
  <pre><code>df &lt;- data.frame(a = rnorm(1e3), b = rnorm(1e3))
  df$a &lt;- cut(df$a , breaks=quantile(df$a, probs = seq(0, 1, 0.2)))
  </code></pre>
  
  <p>and it would be done. However, I strongly prefer to do it with the use of some <code>dplyr</code> function (<code>mutate</code>, I suppose) in the <code>chain</code> sequence of other actions I do perform over my <code>data.frame</code>. </p>