title: Why does Enumerable not have a length attribute in Ruby?
body: <p>At least in Ruby 1.9.3, <a href="http://ruby-doc.org/core-1.9.3/Enumerable.html" rel="nofollow noreferrer"><code>Enumerable</code></a> objects do not have a <code>length</code> attribute.  Why is this?</p>