python学习04——列表的操作

 1 # create a mapping of state to abbreviation
 2 states = {
 3     ‘Oregon‘: ‘OR‘,
 4     ‘Florida‘: ‘FL‘,
 5     ‘California‘: ‘CA‘,
 6     ‘Michigan‘: ‘MI‘
 7 }
 8 
 9 # create a basic set of states and some cities in them
10 cities = {
11     ‘CA‘: ‘San Francisco‘,
12     ‘MI‘: ‘Detroit‘,
13     ‘FL‘: ‘Jacksonville‘
14 }
15 
16 # add some more cities
17 cities[‘NY‘] = ‘New York‘
18 cities[‘OR‘] = ‘Portland‘
19 
20 # print out some cities
21 print ‘-‘ * 10
22 print "NY State has: ", cities[‘NY‘]
23 print "OR State has: ", cities[‘OR‘]
24 
25 # print some states
26 print ‘-‘*10
27 print "Michigan‘s abbreviation is: ", states[‘Michigan‘]
28 print "Florida‘s abbreviation is: ", states[‘Florida‘]
29 
30 # do it by using the state then cities dict
31 print ‘-‘*10
32 print "Michigan has: ", cities[states[‘Michigan‘]]
33 print "Florida has: ", cities[states[‘Florida‘]]
34 
35 # print every state abbreviation
36 print ‘-‘*10
37 for state, abbrev in states.items():
38     print "%s is abbreviated %s" % (state, abbrev)
39 
40 # print every city in state   (why not sequence)
41 print ‘-‘*10
42 for abbrev, city in cities.items():
43     print "%s has the city %s" % (abbrev, city)
44 
45 # now do both at the same time
46 print ‘-‘*10
47 for state, abbrev in states.items():
48     print "%s state is abbreviated %s and has city %s" % (
49         state, abbrev, cities[abbrev])
50 
51 print ‘-‘*10
52 # safely get a abbreviation by state that might not be there
53 state = states.get(‘Texas‘, None)
54 
55 if not state:
56     print "Sorry, no Texas."
57 
58 # get a city with a default value
59 city = cities.get(‘TX‘, ‘Does Not Exist‘)
60 print "The city for the state ‘TX‘ is: %s" % city