ex39.字典，可爱的字典（我的程序注重细节，和笨方法有不一样的地方，请注意）

states = {
"Oregon": 'OR',
"Florida": 'FL',
"California": 'CA',
"New York": "NY",
"Michigan": "MI"
}

cities = {
'CA': 'San Francisco',
'MI': 'Detroit',
'FL': 'Jacksonville',
}

cities['NY'] = 'New York' #添加进cities这个字典的尾部。
cities['OR'] = 'Portland'

print('-'*10)
print("NY State has: ",cities['NY'])
print("OR state has: ",cities['OR'])

print('-'*10)
print("Michigan's abbreviation is:",states['Michigan'])
print("Florida's abbreviation is:",states['Florida'])

print('-'*10)
print("Michigan has: ", cities[states['Michigan']])
print("Florida has: ", cities[states['Florida']])

print('-'*10)
for state,abbrev in states.items():
print(f'{state} is abbreviated {abbrev}')
print(states.items())

print('-'*10)
for abbrev,city in cities.items():
print(f'{abbrev} has the city {city}')

print('-'*10)
for state,abbrev in states.items():
print(f'{state} state is abbreviated {abbrev}')
print(f'and has city {cities[abbrev]}')

print('-'*10)

state = states.get("Texas")
print(state)

if not state:
print("Sorry, no Texas.")

city = cities.get('TX', 'Does Not Exist')
print(f"The city for the state 'TX' is {city}. ")