title: I'm looking for an elegant way to create a vector of tuple_element from a vector of tuple
body: <pre><code>typedef std::tuple&lt;A, B, C&gt; TUPLE;
  typedef std::vector&lt;TUPLE&gt; TUPLE_VECTOR;
  typedef std::vector&lt;A&gt; A_VECTOR;
  </code></pre>
  
  <p>I would like to find the most elegant way of creating an A_VECTOR from a TUPLE_VECTOR. </p>