title: Python Dict Comprehension to Create and Update Dictionary
body: <p>I have a list of dictionaries (data) and want to convert it into dictionary (x) as below. 
  I am using following ‘for loop’ to achieve.</p>
  
  <pre><code>data = [{'Dept': '0123', 'Name': 'Tom'},
          {'Dept': '0123', 'Name': 'Cheryl'},
          {'Dept': '0123', 'Name': 'Raj'},
          {'Dept': '0999', 'Name': 'Tina'}]
  x = {}
  
  for i in data:
      if i['Dept'] in x:
          x[i['Dept']].append(i['Name'])
      else:
          x[i['Dept']] = [i['Name']]
  
  Output:
  x -&gt; {'0999': ['Tina'], '0123': ['Tom', 'Cheryl', 'Raj']}
  </code></pre>
  
  <p>Is it possible to implement the above logic in dict comprehension or any other more pythonic way?</p>