python 字符串格式化 ( 百分号 & format )

Python的字符串格式化有两种方式: 百分号方式、format方式

百分号的方式相对来说比较老，而format方式则是比较先进的方式，企图替换古老的方式，目前两者并存。

----百分号

1 tpl = "i am %s" % "alex"

2 #i am alex

3

4 tpl = "i am %s age %d" % ("alex", 18)

5 #i am alex age 18

6

7 tpl = "i am %(name)s age %(age)d" % {"name": "alex", "age": 18}

8 #i am alex age 18

9

10 tpl = "percent %.2f" % 99.97623

11 #percent 99.98

12

13 tpl = "i am %(pp).2f %%" % {"pp": 123.425556, }

14 #i am 123.43 %

View Code

 ----format

1 tpl = "i am {}, age {}, {}".format("seven", 18, 'alex')

2 #i am seven, age 18, alex

3 tpl = "i am {}, age {}, {}".format(*["seven", 18, 'alex'])

4 #i am seven, age 18, alex

5 tpl = "i am {0}, age {1}, really {0}".format("seven", 18)

6 #i am seven, age 18, really seven

7 tpl = "i am {0}, age {1}, really {0}".format(*["seven", 18])

8 #i am seven, age 18, really seven

9 tpl = "i am {name}, age {age}, really {name}".format(name="seven", age=18)

10 #i am seven, age 18, really seven

11 tpl = "i am {name}, age {age}, really {name}".format(**{"name": "seven", "age": 18})

12 #i am seven, age 18, really seven

13 tpl = "i am {0[0]}, age {1[1]}, really {0[2]}".format([1, 2, 3], [11, 22, 33])

14 #i am 1, age 22, really 3

15 tpl = "i am {:s}, age {:d}, money {:f}".format("seven", 18, 88888.1)

16 #i am seven, age 18, money 88888.100000

17 tpl = "i am {:s}, age {:d}".format(*["seven", 18])

18 #i am seven, age 18

19 tpl = "i am {name:s}, age {age:d}".format(name="seven", age=18)

20 #i am seven, age 18

21 tpl = "i am {name:s}, age {age:d}".format(**{"name": "seven", "age": 18})

22 #i am seven, age 18

23 tpl = "numbers: {:b},{:o},{:d},{:x},{:X}, {:%}".format(15, 15, 15, 15, 15, 15.87623, 2)

24 #numbers: 1111,17,15,f,F, 1587.623000%

25 tpl = "numbers: {:b},{:o},{:d},{:x},{:X}, {:%}".format(15, 15, 15, 15, 15, 15.87623, 2)

26 #numbers: 1111,17,15,f,F, 1587.623000%

27 tpl = "numbers: {0:b},{0:o},{0:d},{0:x},{0:X}, {0:%}".format(15)

28 #numbers: 1111,17,15,f,F, 1500.000000%

29 tpl = "numbers: {num:b},{num:o},{num:d},{num:x},{num:X}, {num:%}".format(num=15)

30 #numbers: 1111,17,15,f,F, 1500.000000%

31 import math

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

33 #The value of PI is approximately 3.14159265359.

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

35 #The value of PI is approximately 3.141592653589793.

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

37 #The value of PI is approximately 3.142.

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

39 for name, phone in table.items():

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

41 '''

42 Dcab ==> 7678

43 Jack ==> 4098

44 Sjoerd ==> 4127

45 '''

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

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

48 #Jack: 4098; Sjoerd: 4127; Dcab: 8637678

View Code

参考文章