title: R list get first item of each element
body: <p>This should probably be very easy for someone to answer but I have had no success on finding the answer anywhere.</p>
  
  <p>I am trying to return, from a list in R, the first item of each element of the list.</p>
  
  <pre><code>&gt; a
  [1] 1 2 3
  &gt; b
  [1] 11 22 33
  &gt; c
  [1] 111 222 333
  &gt; d &lt;- list(a = a,b = b,c = c)
  &gt; d
  $a
  [1] 1 2 3
  
  $b
  [1] 11 22 33
  
  $c
  [1] 111 222 333
  </code></pre>
  
  <p>Based on the construction of my list d above, I want to return a vector with three values: </p>
  
  <pre><code>return  1 11 111
  </code></pre>