1、
>>> a = "good"
>>> a.ljust(1) 'good'
>>> a.ljust(10) ## 左對齊 'good '
>>> a.ljust(10,"-") ## 左對齊,以-填充多余寬度 'good------'
>>> a.ljust(20,"x") 'goodxxxxxxxxxxxxxxxx'
>>> a 'good'
>>> a.center(2) 'good'
>>> a.center(10) ## 中間對齊 ' good '
>>> a.center(10,"x") 'xxxgoodxxx'
>>> a.rjust(3) 'good'
>>> a.rjust(10) ##右對齊 ' good'
>>> a.rjust(10,"y") 'yyyyyygood'