title: r - Nesting multiple Functions via Apply
body: <p>I would like to find the number of missing values in a data set similar to mtcars using is.na and sum.</p>
  <p>Here is my code:</p>
  <pre><code>x &lt;- apply(mtcars, 2, is.na)
  y &lt;- apply(x, 2, sum)
  </code></pre>
  <p>However this is ugly.  Is their a way to do the equivalent of:</p>
  <pre><code>z &lt;- apply(mtcars, 2, sum(is.na))
  </code></pre>