Michael Spencer wrote: > [EMAIL PROTECTED] wrote: > > Kent Johnson wrote: > > > >>[EMAIL PROTECTED] wrote: > >> > >>>p.s. the reason I'm not sticking to reversed or even reverse : > > > > suppose > > > >>>the size of the list is huge. > >> > >>reversed() returns an iterator so list size shouldn't be an issue. > >> > >>What problem are you actually trying to solve? > >> > >>Kent > >> > > > > > > Oh, you are right. > > > > Actually, it's more complicated than simple reversion. The list order > > should be somewhat "twisted" and the list is big. > > > > For example, > > > > [1,2,3,4,5,6,7,8,9,10] > > > > --> [10,9,8,7,6,1,2,3,4,5] > > > > so __getitem__(self,i) => __getitem__(self,-i-1) if i<len(size)/2, > > otherwise __getitem__(self,i-len(size)/2) > > > > I'd like to have TwistedList class that takes in an original list and > > pretends as if it is twisted actually. However, I have to have > > duplicate codes here and there to make it act like a "list", say assert > > twisted_list == [10,9,...] and for each in twisted_list and etc. > > > If you want a twisted 'view' of an existing list, then a wrapper makes most sense. > > If, however, you only need the twisted version, why not simply override > list.__init__ (and extend, append etc... as required): > > >>> class rev_list(list): > ... def __init__(self, iterable): > ... list.__init__(self, iterable[::-1]) > ... > >>> l = rev_list([1,2,3]) > >>> l > [3, 2, 1] > > Michael
Thank you but your advice doesn't fit in my case since I want to keep the memory usage and the initial time minimum. iterable[::-1] would build another list and it would take big memory and time during reversing if iterable were huge. (and the "iterable" wouldn't be garbage-collected because I want to keep a reference to it) -- http://mail.python.org/mailman/listinfo/python-list
