Not very Pythonic

  for i in range(len(records)):
    scores[i] = score(records[i])

Better

  for i, record in enumerate(records):
    scores[i] = score(record)

Best

  scores = [score(record) for record in records]

Raymond Hettinger (Python core dev): https://gist.github.com/bespokoid/205efd91546ddb16b210678830...