title: Pythonic way to compare two lists and print the unmatched items?
body: <p>I have two Python lists of dictionaries, <code>entries9</code> and <code>entries10</code>. I want to compare the items and write joint items to a new list called <code>joint_items</code>. I also want to save the unmatched items to two new lists, <code>unmatched_items_9</code> and <code>unmatched_items_10</code>.</p>
  
  <p>This is my code. Getting the <code>joint_items</code> and <code>unmatched_items_9</code> (in the outer list) is quite easy: but how do I get <code>unmatched_items_10</code> (in the inner list)?</p>
  
  <pre><code>for counter, entry1 in enumerate(entries9):
      match_found = False
      for counter2,entry2 in enumerate(entries10):
          if match_found:
              continue
          if entry1[a]==entry2[a] and entry1[b]==entry2[b]: # the dictionaries only have some keys in common, but we care about a and b
              match_found = True
              joint_item = entry1
              joint_items.append(joint_item)
              #entries10.remove(entry2) # Tried this originally, but realised it messes with the original list object!
      if match_found:
          continue
      else: 
          unmatched_items_9.append(entry1)
  </code></pre>
  
  <p>Performance is not really an issue, since it's a one-off script. </p>