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    12   4    83   9   274  16   645  25  1256  36  2167  49  3438  64  5129  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    12   4    83   9   274  16   645  25  1256  36  2167  49  3438  64  5129  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'