How do I implement a circular buffer in Python?

Question

I have a matrix for instance

a=[12,2,4,67,8,9,23]

and I would like a code that appends a value say 45 to it and removes the first value '12' so in essence I want to make

a = [2,4,67,8,9,23,45]

I want to work with regular matrices not numpy matrices so I can't use hstack or vstack How do I do this in python? Any help would be appreciated, thanks

Answer 1

Use a deque.

http://docs.python.org/2/library/collections.html#collections.deque

>>> import collections
>>> d = collections.deque(maxlen=7)
>>> d.extend([12,2,4,67,8,9,23])
>>> d.append(45)
>>> print d
deque([2, 4, 67, 8, 9, 23, 45], maxlen=7)

Answer 2

You can do this:

a=[12,2,4,67,8,9,23]
a.append(45)
a.pop(0)