习题38 列表的操作 # create a mapping of state to an abbreviation states = { 'Oregon': 'OR', 'Florida': 'FL', 'California': 'CA', 'New York': 'NY', 'Michigan': 'MI' } # create a basic set of states and some cities in them cities = { 'CA': 'San Francisco', 'MI': 'Detroit', 'F