no shift/unshift?

[Gerrit Holl]

Michael P. Soulier schreef op vrijdag 21 februari om 21:24:23 +0000:
>     Hello,
> 
>     I was wondering, is there no built-in way to pull values off and on to a
> list in python? append and pop are find if you are working with the right
> side, but if you need to work with both, having something like shift and
> unshift from perl would be nice. 
>     If I just need to simulate a stack, I'll reverse the list if need be, but
> sometimes I want to manipulate both sides. 

Does this do what you want?

 19 >>> class Mylist(list):
 19 ...  def shift(self, val):
 19 ...   self.insert(0, val)
 19 ...   return self.pop()
 19 ...
 20 >>> l=Mylist(range(5))
 21 >>> l
[0, 1, 2, 3, 4]
 22 >>> l.shift('bla')
4
 23 >>> l
['bla', 0, 1, 2, 3]

yours,
Gerrit.

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