python---字典

info = {
    "stu001":"fengxiaoli",
    "stu002":"cx",
    "stu003":"wyc",
    "stu004":"ljh",
}


###-----------------循环字典
for i in info:              #推荐使用
    print(i,info[i])

for k,v in info.items():    #不推荐，因为它是先转化为列表在打印，数据量的时候数据会很慢
    print(k,v)
    
    
###-----------------查询
print("stu001" in info)     #判断key是否在字典中，同py2中 info.has_key("stu001")
print(info.get("stu002"))   #通过key获取value，推荐使用
print(info["stu001"])
print(info)  
    
    
###-----------------修改
info["stu003"] = "fzl"        #有那个key就修改，没有新增
info["stu005"] = "fzl"
print(info)


###-----------------删除
del info                       #删除整个字典
del info["stu005"]
info.pop("stu004")
info.popitem()                 #随机删除一组


###-----------------合并两个字典
b = {
    "stu001":"fxl",
    3:5,
    4:8,
}
info.update(b)      #合并字典info和字典b，有重复的就更新，不重复的就合并
print(info)


###-----------------把字典转成列表
print(info.items())


###-----------------初始化一个字典
c = dict.fromkeys([7,8,9],"test")
print(c)
#输出{8: 'test', 9: 'test', 7: 'test'}

c1 = dict.fromkeys([7,8,9],{1:"feng",2:"cx",3:"fxl"})
print(c1)
#输出{8: {1: 'feng', 2: 'cx', 3: 'fxl'}, 9: {1: 'feng', 2: 'cx', 3: 'fxl'}, 7: {1: 'feng', 2: 'cx', 3: 'fxl'}}

c1[8][2]="xia"      #类似浅copy，二级字典中数据指向同一内存地址，修改一个所有都改变
print(c1)
#输出{8: {1: 'feng', 2: 'xia', 3: 'fxl'}, 9: {1: 'feng', 2: 'xia', 3: 'fxl'}, 7: {1: 'feng', 2: 'xia', 3: 'fxl'}}
   
   

###-----------------多级字典
info2 = {
    "stu001":{"fxl":["性别：男","年龄：21"]},
    "stu002":{"cx":["性别：女","年龄：25"]},
    "stu003":{"fzl":["性别：男","年龄：35"]},
}
info2["stu001"]["fxl"][1] = "年龄：23"            #修改
info2.setdefault("stu004",{"ljh":["性别：女","年龄：40"]})     #增加，如果字典中有这个key就不改变原值，没有就新建
print(info2)

# Author:fengxiaoli

Data={
    "重庆":{
        "綦江":{
            "永城":["永城中学","永城小学"],
            "隆盛":["隆盛中学","隆盛小学"],
            "三角":["三角中学","三角小学"],
            "丁山":["丁山中学","丁山小学"],
        },
        "永川":{},
        "江北":{},
        "沙坪坝":{},
    },
    "北京":{},
    "上海":{},
    "天津":{}
}
while True:
    for i in Data:
        print(i)
    choice1=input("1>>>>>")
    if choice1 in Data:
        while True:
            for j in Data[choice1]:
                print(j)
            choice2 = input("2>>>>>")
            if choice2 in Data[choice1]:
                while True:
                    for k in Data[choice1][choice2]:
                        print(k)
                    choice3= input("3>>>>>")
                    if choice3 in Data[choice1][choice2]:
                        while True:
                            for t in Data[choice1][choice2][choice3]:
                                print(t)
                            choice4= input("最后一层,返回按b:")
                            if choice4 == "b":
                                break
                            elif choice4=="q":
                                exit()
                    if choice3 == "b":
                        break
                    elif choice3 == "q":
                        exit()
            if choice2 == "b":
                break
            elif choice2 == "q":
                exit()