定义及应用
定义
<span style="font-size:18px;">stuff = {'name': 'Zed', 'age': 36, 'height': 6*12+2}#key:value pairs</span>
实例
# create a mapping of state to 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', 'FL': 'Jacksonville' } # add some more cities cities['NY'] = 'New York' cities['OR'] = 'Portland' # print out some cities print '-' * 10 print "NY State has: ", cities['NY'] print "OR State has: ", cities['OR'] # print some states print '-' * 10 print "Michigan's abbreviation is: ", states['Michigan'] print "Florida's abbreviation is: ", states['Florida'] # do it by using the state then cities dict print '-' * 10 print "Michigan has: ", cities[states['Michigan']] print "Florida has: ", cities[states['Florida']] # print every state abbreviation print '-' * 10 for state, abbrev in states.items(): print "%s is abbreviated %s" % (state, abbrev) # print every city in state print '-' * 10 for abbrev, city in cities.items(): print "%s has the city %s" % (abbrev, city) # now do both at the same time print '-' * 10 for state, abbrev in states.items(): print "%s state is abbreviated %s and has city %s" % ( state, abbrev, cities[abbrev]) print '-' * 10 # safely get a abbreviation by state that might not be there state = states.get('Texas', None) if not state: print "Sorry, no Texas." # get a city with a default value city = cities.get('TX', 'Does Not Exist')#if exist key=='TX',city=value,or city='Dose Not Exist' print "The city for the state 'TX' is: %s" % city
output
---------- NY State has: New York OR State has: Portland ---------- Michigan's abbreviation is: MI Florida's abbreviation is: FL ---------- Michigan has: Detroit Florida has: Jacksonville ---------- California is abbreviated CA Michigan is abbreviated MI New York is abbreviated NY Florida is abbreviated FL Oregon is abbreviated OR ---------- FL has the city Jacksonville CA has the city San Francisco MI has the city Detroit OR has the city Portland NY has the city New York ---------- California state is abbreviated CA and has city San Francisco Michigan state is abbreviated MI and has city Detroit New York state is abbreviated NY and has city New York Florida state is abbreviated FL and has city Jacksonville Oregon state is abbreviated OR and has city Portland ---------- Sorry, no Texas. The city for the state 'TX' is: Does Not Exist