python--字典工厂函数dict()

Posted 2020-08-15

 1 dic = {"name" : "wangmo" ,"age" : 18}
 2 
 3 #dic.clear() #清空字典
 4 print(dic)
 5 #{}
 6 
 7 dic1=dic.copy() #复制字典
 8 print(dic1)
 9 #{‘name‘: ‘wangmo‘, ‘age‘: 18}
10 
11 dic1=dict.fromkeys("hello",1) #快速生成字典
12 print(dic1)
13 #{‘o‘: 1, ‘h‘: 1, ‘l‘: 1, ‘e‘: 1}
14 
15 print(dic.get("name")) #查看字典中是否存在此key，没有提示none
16 #wangmo
17 
18 print(dic["name"]) #查看字典中是否存在此key,没有会报错
19 #wangmo
20 
21 print(dic.items()) #将每对key-value表示成列表中元组的形式
22 #dict_items([(‘name‘, ‘wangmo‘), (‘age‘, 18)])
23 
24 for i in dic.items(): #循环输出每个项目
25     print(i)
26 # (‘name‘, ‘wangmo‘)
27 # (‘age‘, 18)
28 
29 for k,v in dic.items(): #循环输出每个项目
30     print(k,v)
31 # name wangmo
32 # age 18
33 
34 print(dic.keys()) #输出字典的key值
35 #dict_keys([‘name‘, ‘age‘])
36 
37 for i in dic.keys(): #循环输出字典的key值
38     print(i)
39 # name
40 # age
41 
42 for i in dic.keys(): #可以循环输出key和value
43     print(‘key is %s,value is %s‘ %(i,dic[i]))
44 # key is age,value is 18
45 # key is name,value is wangmo