a couple of things I don't understand wrt lists

[88888 Dihedral]

Serhiy Storchaka於 2013年4月17日星期三UTC+8下午5時35分07秒寫道：
> 17.04.13 07:57, Larry Hudson написав(ла):
> 
> > So using a list comprehension you can do it in two lines:
> 
> >
> 
> > def get_rule(num):
> 
> >      bs = bin(num)[2:]
> 
> >      return [0] * (8 - len(bs)) + [int(i) for i in bs]
> 
> 
> 
> You can do it in one line!
> 
> 
> 
> def get_rule(num):
> 
>       return list(map(int, '{:08b}'.format(num)))

Well, a new object is returned and can be used. 
Then who is going to clean up the object when required?