python中的字符串格式函数str.format()

1 #使用str.format()函数  

2  

3 #使用'{}'占位符  

4 print('I\'m {},{}'.format('Hongten','Welcome to my space!'))  

5 >>> I'm Hongten,Welcome to my space!  

6 print('#' * 40)  

7  

8 #也可以使用'{0}','{1}'形式的占位符  

9 print('{0},I\'m {1},my E-mail is {2}'.format('Hello','Hongten','[e-mail]')) 

>>> Hello,I'm Hongten,my E-mail is [e-mail]

10 #可以改变占位符的位置 

11 print('{1},I\'m {0},my E-mail is {2}'.format('Hongten','Hello','[e-mail]')) 

12 >>> Hello,I'm Hongten,my E-mail is [e-mail]

13 print('#' * 40) 

14 ########################################

15 #使用'{name}'形式的占位符 

16 print('Hi,{name},{message}'.format(name = 'Tom',message = 'How old are you?')) 

17 >>> Hi,Tom,How old are you?

18 print('#' * 40) 

19 ########################################

20 #混合使用'{0}','{name}'形式 

21 print('{0},I\'m {1},{message}'.format('Hello','Hongten',message = 'This is a test message!')) 

22 >>> Hello,I'm Hongten,This is a test message!

23 print('#' * 40) 

24 ########################################

25 #下面进行格式控制 

26 import math 

27 print('The value of PI is approximately {}.'.format(math.pi)) 

>>> The value of PI is approximately 3.141592653589793.

28 print('The value of PI is approximately {!r}.'.format(math.pi)) 

>>> The value of PI is approximately 3.141592653589793.

29 print('The value of PI is approximately {0:.3f}.'.format(math.pi)) 

>>> The value of PI is approximately 3.142.

30

31 

32 table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 7678} 

33 for name, phone in table.items(): 

34 print('{0:10} ==> {1:10d}'.format(name, phone)) 

35 >>> 

Dcab   ==>       7678
Jack   ==>       4098
Sjoerd ==>       4127

36 

37 table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 8637678} 

38 print('Jack: {0[Jack]:d}; Sjoerd: {0[Sjoerd]:d}; ''Dcab: {0[Dcab]:d}'.format(table))

>>> Jack: 4098; Sjoerd: 4127; Dcab: 8637678