Python--字典操作

字典的增删改查及遍历
 1 info = {
 2     "stu3":"yuanyuan",
 3     "stu1":"tianjie",
 4     "stu2":"wangxinlin"
 5 }
 6 print(type(info)) #输出类型
 7 print(info)
 8 print(info["stu1"]) #查找 条件：适用于确定有该键值,没有键值时报错
 9 print(info.get("stu00")) #没有时返回None
10 print(info.get("stu1")) #有就返回value
11 
12 print("stu02" in info) #判断是否存在该数据，如果存在返回True，不存在返回False
13 # info.has_key("stu1") # 适用于py2
14 
15 info["stu2"] = "fenglubei"  #修改
16 print(info)
17 info["stu4"] = "wangxinlin" #没有该键时新增
18 print(info)
19 
20 del info["stu1"] #删除
21 print(info)
22 
23 info.pop("stu2") #删除特定键值
24 print(info)
25 
26 info.popitem() #随机删
27 print(info)
28 
29 #字典嵌套
30 shuqike = {
31     "gongsi":{
32         "kaifa":["ma","jiaming","jiao","yuan","yaqiong","zhendong"],
33         "yunwei":["yecai","majin"]
34     },
35     "SJS":{
36         "kaifa":["cong","jiang"],
37         "yunwei":["feng","tian","xinlin","yuanyuan"]
38     }
39 }
40 print(shuqike)
41 
42 #查
43 print(shuqike["gongsi"]["kaifa"][2])
44 print(shuqike["SJS"]["yunwei"][2])
45 
46 #改
47 shuqike["gongsi"]["kaifa"][2] = "zhen"
48 print(shuqike)
49 
50 #增加
51 shuqike["gongsi"]["jiagou"] = ["hou","peng"]
52 print(shuqike)
53 
54 #高级
55 zimu = {
56     "大写":["A","B","C"],
57     "小写":["a","b","c"]
58 }
59 print(zimu.keys()) #获取列表里的所有key
60 print(zimu.values()) #获取列表里的所有value
61 
62 # setdefault,在字典里取值，当能取到值时就不动字典，当取不到值时，创建一个
63 zimu.setdefault("qita", [1,2,3])
64 zimu.setdefault("大写", ["D"])
65 print(zimu)
66 
67 #update,存在交叉，更新值，不存在键则新增
68 b = {
69     "小写":"fff",
70     1:2,
71     3:4
72 }
73 zimu.update(b)
74 print(zimu)
75 
76 print(zimu.items()) #字典转列表
77 
78 c = dict.fromkeys([6,7,8],"test") #创建一个字典，key为678，值都为test
79 print(c)
80 
81 d = dict.fromkeys([1,2,3],[1,{"name":"tinajie"},333])
82 print(d)
83 d[3][1]["name"] = "yuanyuan"  #都改，并不是只改一个
84 print(d)
85 
86 #字典的遍历
87 for i in zimu:
88     print(i) #只打印key
89     print(i,zimu[i])
90 
91 for k,v in zimu.items():  #效率低于上面那种，因为要转成列表
92     print(k,v)