title: Turn the list of dictionaries into a single dictionary
body: <p>I've been trying to convert a list of dictionaries into a single dictionary in such a way where each key is <code>&lt;city&gt;, &lt;state&gt;</code> and each value is <code>&lt;county&gt;</code>.</p>
  <p>In short I have  a list that looks like this.</p>
  <pre><code>[{'city': 'Normal', 
    'county': 'Madison County', 
    'state': 'Alabama'},
   {'city': 'Birmingham', 
    'county': 'Jefferson County', 
    'state': 'Alabama'},
   {'city': 'Montgomery', 
    'county': 'Montgomery County', 
    'state': 'Alabama'}]
  </code></pre>
  <p>And I would like to change it into something like this</p>
  <pre><code>{'Normal, Alabama': 'Madison County',
   'Birmingham, Alabama': 'Jefferson County',
   'Montgomery, Alabama': 'Montgomery County'}
  </code></pre>
  <p>I tried dictionary comprehensions but can't seem to add two different keys at once.</p>
  <p>So I know the code below will give me a dictionary with cities and counties for key value pairs</p>
  <pre><code>new_dict = {x['city']: x['county']  for x in counties}
  </code></pre>
  <p>However, how do I add two different keys? Something like <code>new_dict = {x['city','state']: x['county']  for x in counties}</code> won't work.</p>