字符串格式化

string的ljust()、rjust()、center()用来对齐

>>> for x in range(1, 11):

...     print(repr(x).rjust(2), repr(x*x).rjust(3), end=' ')

...     # Note use of 'end' on previous line

...     print(repr(x*x*x).rjust(4))

...

 1   1    1

 2   4    8

 3   9   27

 4  16   64

 5  25  125

 6  36  216

 7  49  343

 8  64  512

 9  81  729

10 100 1000



>>> for x in range(1, 11):

...     print('{0:2d} {1:3d} {2:4d}'.format(x, x*x, x*x*x))

...

 1   1    1

 2   4    8

 3   9   27

 4  16   64

 5  25  125

 6  36  216

 7  49  343

 8  64  512

 9  81  729

10 100 1000

str.zfill()用来给数字型字符串对齐

>>> '12'.zfill(5)

'00012'

>>> '-3.14'.zfill(7)

'-003.14'

>>> '3.14159265359'.zfill(5)

'3.14159265359'