python---对齐
print '0123'.ljust(20, '-')
print '01234'.ljust(20, '-')
print '012356'.ljust(20, '-')
print '0123567'.ljust(20, '-')
print '0123'.ljust(20, '-')
print '01234'.ljust(20, '-')
print '012356'.ljust(20, '-')
print '0123567'.ljust(20, '-')