python基礎之字典操作

字典中的key，只能用不可變的數據類型，數字，字符串，元組皆可以。在存儲時將key值進行哈希，所以只能用不可變的數據類型。

1. len( )返回字典的鍵值對

>>> b={"name":"wang da lu","age":23,"gender":"boy"}
       
>>> len(b)
       
3

2. values( )

>>> b={"name":"wang da lu","age":23,"gender":"boy"}
       
>>> for each in b.values():
       print(each)
wang da lu
23
boy

3. keys( )

>>> b={"name":"wang da lu","age":23,"gender":"boy"}
       
>>> for each in b.keys():
       print(each) 
name
age
gender

 

>>> b={"name":"wang da lu","age":23,"gender":"boy"}
       
>>> for each in b: #默認爲key
       print(each)  
name
age
gender

4. items( )

>>> b={"name":"wang da lu","age":23,"gender":"boy"}
       
>>> for each in b.items():
       print(each)
('name', 'wang da lu')
('age', 23)
('gender', 'boy')

5. 

>>> b={"name":"wang da lu","age":23,"gender":"boy"}
>>> for A,B in b.items():
	print("Hello:%s,Hello:%s" %(A,B))
Hello:name,Hello:wang da lu
Hello:age,Hello:23
Hello:gender,Hello:boy