title: Implicit variable reference in R
body: <p>How can I evaluate <code>c[,2]</code> through a call to <code>z</code>?</p>
  
  <pre><code>a &lt;- c(1,2,3)
  b &lt;- c(4,5,6)
  c &lt;- cbind(a,b)
  z &lt;- "c[,2]"
  </code></pre>
  
  <p><code>eval(z)</code> is not working.</p>