看下面的例子就会明白了：

复制代码 代码如下:

print '|','*'.ljust(10),'|'

print '|','*'.ljust(10,'-'),'|'

print '|','*'.rjust(10,'-'),'|'

print '|','*'.center(10,'-'),'|'

for a in range(1, 6):

print 'a = '.ljust(5), repr(a).ljust(10), 'b = '.ljust(5), repr(a * 2)

输出结果:

| * |

| *--------- |

| ---------* |

| ----*----- |

a = 1 b = 2

a = 2 b = 4

a = 3 b = 6

a = 4 b = 8

a = 5 b = 10