字典 # key-value type
info = {
‘stu1101’: "Teng",
'stu1102': "Long",
}
print(info) # dict是无序的，key必须唯一，天生去重
print(info["stu1101"]) #查询
print(info.get("stu1105") #稳健查询
info["stu1101"] = "TEND LAN" #udpate
info["stu1104"] = "Alex" # 创建
del info["Long"] #del
info.popitem() #随机删除一个
info.pop("stut1101") #删除stut1101
print（‘stutter101‘ in info）#判断是否Ture
b ={
'stut1101": "Louie",
1:3,
2:55,
}
info.update(b) #相同的key记录更新，不同key则添加，1和2就是新的key
print(info)
###字符串变字典
eval()
#多级字典嵌套操作-》树状结构
#多级字典嵌套操作-》树状结构
_area ={
"SH":{"1":("上海火车站","人民广场"),
"2":("南京西路","中山公园","静安寺")
},
"BJ":{"1":"没有数据",}
}
for i in _area:
print(i) # print(i,_area[i])
for j in _area[i]:
print("----",j,_area[i][j])
for h in _area[i][j]:
print("--------",h)
------------------------------- 以上似乎有问题 ----------------------------------
catalog ={
"数学": {
“AAA”: "代数”,
“BBB”: “几何”,
}，
“语文”： {
"shige": "诗文",
"sanfan": "散文",
}，
}
catalog["语文"]["shige”][1] = "诗歌是唐朝的” #update
info.values()
info.keys()
catalog.setdefualt("英语"，{"English": [1,2]}) #create
info.items()
c = dict.fromkeys([7,8,9]) #初始化一个新的字典
print(c) #创建字典为空
d = dict.fromkeys([7,8,9],"test") #3个共享一个内存地址指针，update则一起update其中所有的内容
print(d)
#字典循环
for i in info #效率比下面高
print(i, info[i])
for k,v in info.items():
print(k,v)
### 三级菜单案例
###定义三级字典
exit_flag = False
while not exit_flag :
for i in data:
print(i)
choice = input("选择>:")
if choice in data
while not exit_flag:
for i2 in data[choice]:
print("\t",i2)
choice2 = input("选择进入>>>:")
if choice2 in data[choice]:
while not exit_flag:
for i3 in data[choice][choice2]" :
print("\t\t", i3)
choice3 = input("选择进入3>>>:")
if choice3 in data[choice][choice2]:
for i4 in data[choice][choice2][choice3] :
print("\t\t",i4)
choice4 = input("最后一层，按b返回>>>:")
if choice4=="b":
break
#pass 什么也不做
elif choice4 =="q":
exit_flag ="True"
if choice3=="b":
break
elif choice3 =="q":
exit_flag ="True"
if choice2=="b":
break
elif choice2 =="q":
exit_flag ="True"