dictionary # key-value type
info = {
‘stu1101’: "Teng",
'stu1102': "Long",
}
print(info) # The dict is unordered, the key must be unique, and it is inherently de-duplicated
print(info["stu1101"]) #Query
print(info.get("stu1105") #Robust query
info["stu1101"] = "TEND LAN" #udpate
info["stu1104"] = "Alex" # create
del info["Long"] #del
info.popitem() #Delete one randomly
info.pop("stut1101") #delete stut1101
print('stutter101' in info) #Determine whether it is True
b ={
'stut1101": "Louie",
1:3,
2:55,
}
info.update(b) #The same key record is updated, different keys are added, 1 and 2 are new keys
print(info)
### string to dictionary
eval()
#Multi-level dictionary nesting operation - "tree structure
#Multi-level dictionary nesting operation-"tree structure_area
={
"SH":{"1":("Shanghai Railway Station","People's Square"),
"2":("Nanjing West Road","Zhongshan Park","Jing'an Temple")
},
"BJ":{"1":"No data",}
}
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)
-- ----------------------------- There seems to be a problem with the above ----------------- -----------------
catalog ={
"math": {
"AAA": "Algebra",
"BBB": "Geometry",
}，
"language": {
"shige": "诗文",
"sanfan": "散文",
}，
}
catalog["language"]["shige"][1] = "Poetry is from the Tang Dynasty" #update
info.values()
info.keys()
catalog.setdefualt("英语"，{"English": [1,2]}) #create
info.items()
c = dict.fromkeys([7,8,9]) #Initialize a new dictionary
print(c) #create dictionary is empty
d = dict.fromkeys([7,8,9],"test") #3 share a memory address pointer, update updates all of them together
print(d)
#dictionary loop
for i in info #The efficiency is higher than the following
print(i, info[i])
for k,v in info.items():
print (k, v)
### Three-level menu case
###Define three-level dictionary
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("Choose to enter >>>:")
if choice2 in data[choice]:
while not exit_flag:
for i3 in data[choice][choice2]" :
print("\t\t", i3)
choice3 = input("Choose to enter 3>>>:")
if choice3 in data[choice][choice2]:
for i4 in data[choice][choice2][choice3] :
print("\t\t",i4)
choice4 = input("The last layer, press b to return >>>:")
if choice4=="b":
break
#pass does nothing
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"