title: in R, extract part of object from list
body: <p>I'm just learning R and having a hard time wrapping my head around how to extract elements from objects in a list.  I've parsed a json file into R giving me list object.  But I can't figure out how, from there, to extract various json elements from the list.  here's a truncated look at how my data appears after parsing the json:</p>
  
  <pre><code> &gt; #Parse data into R objects#
   &gt; list.Json= fromJSON(,final.name, method = "C")
   &gt; head(listJson,6)
  [[1]]
  [[1]]$contributors
  NULL
  
  [[1]]$favorited
  [1] FALSE
  
  ...[truncating]...
  [[5]]
  [[5]]$contributors
  NULL
  
  [[5]]$favorited
  [1] FALSE
  </code></pre>
  
  <p>I can figure out how to extract the favorites data for one of the objects in the list</p>
  
  <pre><code>&gt; first.object=listJson[1]
  &gt; ff=first.object[[1]]$favorited
  &gt; ff
  [1] FALSE
  </code></pre>
  
  <p>But I'm very confused about how to extract favorited for all objects in the list.  I've looked into sappily, is that the correct approach?  Do I need to put the above code into a for...next loop? </p>