EX39
1 # create a mapping of state to abbreviation 2 states = { 3 'Oregon': 'OR', 4 'Florida': 'FL', 5 'California': 'CA', 6 'New York': 'NY', 7 'Michigan': 'MI' 8 } 9 10 # create a basic set of states and some cities in them 11 cities = { 12 'CA': 'San Francisco', 13 'MI': 'Detroit', 14 'FL': 'Jacksonville' 15 } 16 17 # add some more cities 18 cities['NY'] = 'New York' 19 cities['OR'] = 'Portland' 20 21 # print out some cities 22 print '-' * 10 23 print "NY State has: ", cities['NY'] 24 print "OR State has: ", cities['OR'] 25 26 # print some states 27 print '-' * 10 28 print "Michigan's abbreviation is: ", states['Michigan'] 29 print "Florida's abbreviation is: ", states['Florida'] 30 31 # do it by using the state then cities dict 32 print '-' * 10 33 print "Michigan has: ", cities[states['Michigan']] 34 print "Florida has: ", cities[states['Florida']] 35 36 # print every state abbreviation 37 print '-' * 10 38 for state, abbrev in states.items(): 39 print "%s is abbreviated %s" % (state, abbrev) 40 41 # print every city in state 42 print '-' * 10 43 for abbrev, city in cities.items(): 44 print "%s has the city %s" % (abbrev, city) 45 46 # now do both at the same time 47 print '-' * 10 48 for state, abbrev in states.items(): 49 print "%s state is abbreviated %s and has city %s" % ( 50 state, abbrev, cities[abbrev]) 51 52 print '-' * 10 53 # safely get a abbreviaiton by state that might not be there 54 state = states.get('Texas', None) 55 56 if not state: 57 print "Sorry, no Texas." 58 59 # get a city with a default value 60 city = cities.get('TX', 'Does Not Exist') 61 print "The city for the state 'TX' is: %s" % city
1、对应行38-39,打印的顺序为何是以C->M->N->F->O的顺序?而在第二张图是又是以F->C->M的顺序打印?
此篇先保留,没弄懂这个打印出来的意义在哪里