Python deque

>>> from collections import deque
 
>>> d = deque([1,2])
deque([1, 2])
 
>>> d.appendleft(0)
deque([0, 1, 2])
 
>>> d.append(3)
deque([0, 1, 2, 3])
 
>>> d.extend([4,5])
deque([0, 1, 2, 3, 4, 5])
 
>>> d.extendleft([-1])
deque([-1, 0, 1, 2, 3, 4, 5])
 
>>> d.pop()
5
deque([-1, 0, 1, 2, 3, 4])
 
>>> d.popleft()
-1
deque([0, 1, 2, 3, 4])
 
>>> d.remove(4)
deque([0, 1, 2, 3])
 
>>> d.count(3)
1
 
>>> d.index(3)
3
 
>>> d.rotate()
deque([3, 0, 1, 2])
 
>>> d.rotate(-2)
deque([1, 2, 3, 0])
 
>>> d.reverse()
deque([0, 3, 2, 1])