Python-字典(练习题)

"""练习题"""cities = {
    'Wuhan': {
        'country': 'China',
        'population': '1700',
        'fact': 'nice'    },    
    'New York':{
        'country': 'America',
        'population': '1600',
        'fact': 'good'
    },
    'Paris':{
        'country': 'French',
        'population': '1000',
        'fact': 'normall'    }
}
for city_name,city_info in cities.items():
    print('city_name:'+city_name)
    country = city_info['country']
    population = city_info['population']
    fact = city_info['fact']
    print('country:'+country+'\t'+'population:'+population+'\t'+'fact:'+fact+'\n')

"""添加键和值"""
cities['Wuhan']['history'] = 100
print(cities.items())
"""修改键和值"""
cities['Wuhan']['history'] = 50
print(cities.items())
"""删除键和值"""
del cities['Wuhan']['history']
print(cities.items())