efficient idiomatic queue?

[Raymond Hettinger]

"Alex Martelli" <aleax at aleax.it> wrote in message
news:a20q9p$ej5$1 at serv1.iunet.it...

> class fifo:
>     def __init__(self):
>         self.data = []
>         self.first = 0
>     def head(self):
>         return self.data[self.first]
>     def pop(self):
>         self.first += 1
>         if self.first > len(self.data)/2:
>             self.data = self.data[self.first:]
>             self.first = 0
>     def append(self, value):
>         self.data.append(value)
>
>
> Alex
>

The Python Cookbook has an algorithm for O(n) FIFO queues submitted by
Sébastien Keim.
His approach is interesting and brilliant,

See:  http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/68436

After tightening the code a bit, it looks a like this:

class Fifo:
        stored = [None]
        stored[0] = stored
        def append(self,data):  # to inside
                if len(self.stored) == 1:
                        return self.stored.append(data)
                self.stored[0] = self.stored = [self.stored[0], data]
        def pop(self):  # from outside
                whole = self.stored[0]
                self.stored[0] = whole[0]
                return whole[1]

Raymond Hettinger