title: Boxplot dplyr: Error: non-numeric argument to binary operator
body: <p>I have count the values of a column with dplyr.</p>
  
  <pre><code>yelp_tbl %&gt;% select(name) %&gt;% count(name)
  </code></pre>
  
  <p>The resulting data looks like this:</p>
  
  <pre><code># A tibble: 108,999 x 2
                                    name     n
                                    &lt;chr&gt; &lt;int&gt;
   1                    'do blow dry bar     1
   2                  'Round Table Tours     1
   3                      'S Hundehüttle     1
   4                           # 1 Nails     1
   5 #1 Cochran Buick GMC of Monroeville     1
   6    #1 Cochran Buick GMC of Robinson     1
   7   #1 Cochran Cadillac - Monroeville     2
  </code></pre>
  
  <p>Now I want to make a boxplot of the "n" column.</p>
  
  <pre><code>yelp_tbl %&gt;% select(name) %&gt;% count(name) %&gt;% boxplot(n)
  </code></pre>
  
  <p>But I got this result:</p>
  
  <pre><code>Error in x[floor(d)] + x[ceiling(d)] : 
  non-numeric argument to binary operator
  </code></pre>
  
  <p>Any Idea? Is it because of the function?</p>