python day2 省市三级联动

一.需求

用户交互，显示省市县三级联动的选择

要求：用户输入河北，则打印河北省下的市，用户输入市，则显示该河北省的这个市下的县

二.流程图

dic = {
    "河北": {
        "石家庄": ["鹿泉", "藁城", "元氏"],
        "邯郸": ["永年", "涉县", "磁县"],
    },
    "河南": {
        "郑州":["上街区","二七区","金水区"],
        "商丘":["永成","民权","宁陵"],
    },
    "山西": {
        "大同":["大同","左云","广陵"],
        "太原":["清徐","阳曲","娄烦"],

    },
}
while True:
    province = input('请输入省份包含的市： ').strip()
    if province not in dic:
        print('输入错误')
        continue
    elif len(province) == 0:
        print('输入不正确')
        continue
    else:
        for city in dic.get(province):
            print(city)
        your_choose = input('请输入市查看所有的县： ').strip()
        print(dic.get(province).get(your))