如何返回每个国家/地区作为键,并返回该国家/地区中的城市列表作为值?使用字典和嵌入式列表理解?不使用收藏集
country_city_tuples= [('Netherlands', 'Alkmaar'),
('Netherlands', 'Tilburg'),
('Netherlands', 'Den Bosch'),
('Netherlands', 'Eindhoven'),
('Spain', 'Madrid'),
('Spain', 'Barcelona'),
('Spain', 'Cordoba'),
('Spain', 'Toledo'),
('Italy', 'Milano'),
('Italy', 'Roma')]
答案 0 :(得分:2)
您可以执行以下操作:
my_dict = {item[0]: [subitem for subkey, subitem in country_city_tuples if subkey == item[0]] for item in country_city_tuples}
输出如下:
{'Netherlands': ['Alkmaar', 'Tilburg', 'Den Bosch', 'Eindhoven'], 'Italy': ['Milano', 'Roma'], 'Spain': ['Madrid', 'Barcelona', 'Cordoba', 'Toledo']}