title: Combine unknown number of named lists with the same key names
body: <p>I have a list that may contain 2 or more named list, e.g.:</p>
  
  <pre><code>mylist &lt;- c(list(a = "a1", b = "b1"), list(a = "a2", b = "b2"), list(a = 3, b = 3))
  </code></pre>
  
  <p>Since I know there are always two key names named a and b, I would like to query a and b, so that a would return:</p>
  
  <pre><code>&gt; "a1" "a2" 3
  </code></pre>
  
  <p>b should return a list</p>
  
  <pre><code>&gt; "b1" "b2" 3
  </code></pre>
  
  <p>None of the other existing solutions fit my purpose, as all of them are about merging two lists. However my input as warpped in c() can contain multiple lists.</p>
  
  <p>Do you have any idea?</p>