title: Dictionary comprehensions using two different sources for keys and values
body: <p>I am trying to create a dictionary through a comprehension but I have to use keys from a specific range of numbers and values from a predefined list:</p>
  
  <pre><code>pssmList=[]
  for column in columns:
      pssmList.append(collections.Counter(column))
  
  pssmDict = {key:value for key in range(0, len(pssmList)) for value in 
  pssmList}
  </code></pre>
  
  <p>Now, I know that the Counter object is a type of dict but I need those objects inside of pssmDict assigned to keys from a numerical range specified above and all I get is the last element in pssmList repeated over and over again, although each line should be different (and yes, I checked the list and it really contains different records):</p>
  
  <pre><code> Key   Number         
  0     Counter({'T': 8, 'E': 4, 'P': 2, 'V': 1, 'S': 1, 'D': 1})
  1     Counter({'T': 8, 'E': 4, 'P': 2, 'V': 1, 'S': 1, 'D': 1})
  2     Counter({'T': 8, 'E': 4, 'P': 2, 'V': 1, 'S': 1, 'D': 1})
  3     Counter({'T': 8, 'E': 4, 'P': 2, 'V': 1, 'S': 1, 'D': 1})
  4     Counter({'T': 8, 'E': 4, 'P': 2, 'V': 1, 'S': 1, 'D': 1})
  5     Counter({'T': 8, 'E': 4, 'P': 2, 'V': 1, 'S': 1, 'D': 1})
  </code></pre>
  
  <p>Desired output:</p>
  
  <pre><code> Key   Number         
  0     Counter({'V': 14, 'L': 2, 'A': 1})
  1     Counter({'D': 17}) 
  2     Counter({'F': 17})
  3     Counter({'S': 8, 'W': 5, 'Y': 3, 'T': 1})
  4     Counter({'A': 17})
  5     Counter({'T': 8, 'E': 4, 'P': 2, 'V': 1, 'S': 1, 'D': 1})
  </code></pre>
  
  <p>Does anyone have any idea why this does not work? I've searched StackOverflow for similar problems but either I'm bad at searching or such questions haven't appeared.</p>
  
  <p>Please excuse me if my mistake is trivial, I'm in my third month of learning Python (and coding altogether).</p>