from collections import deque
# 雙向隊列[有序序列] (封裝list)
def deques():
    # 雙向隊列,線程安全,隊列兩端添加和彈出復雜度為O(1),效率很高
    # 創建
    lists = ["A", "B", "C", "D", "E"] # <class ‘list‘>: [‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘]
    queue = deque(lists) # deque([‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘])
    queue = deque(lists, 3) # 3為限制容器大小,隊列滿之後,先添加的元素將擠出另一端的舊元素;
                            # 未指定容器大小將是任意長度, deque([‘C‘, ‘D‘, ‘E‘], maxlen=3)
    queue = deque(range(10)) # deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

    # 添加
    queue.append("F") # 添加到右邊, deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ‘F‘])
    queue.appendleft("G") # 添加到左邊, deque([‘G‘, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ‘F‘])
    queue.extend(range(3)) # 右邊添加iterable元素, deque([‘G‘, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ‘F‘, 0, 1, 2])
    queue.extendleft(range(3)) # 追加到左邊，註意變成了210，deque([2, 1, 0, ‘G‘, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ‘F‘, 0, 1, 2])
    queue.insert(1, "L") # 在指定的index插入元素，deque([2, ‘L‘, 1, 0, ‘G‘, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ‘F‘, 0, 1, 2])
    queue = queue + deque(range(3)) # 合並， deque([2, ‘L‘, 1, 0, ‘G‘, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ‘F‘, 0, 1, 2, 0, 1, 2])
    queue = queue * 3 # n倍

    # 獲取
    queue = deque(lists) # deque([‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘])
    queue2 = queue.copy() # 淺拷貝
    index = queue.index("C") # 獲取索引,未找到拋ValueError異常, 2
    index = queue.index("C", 1) # 可以指定start
    index = queue.index("C", 2, 4) # 可以指定end
    elem = max(queue) # e
    elem = min(queue) #

    # 統計
    count = queue.count("A") # 1

    # 刪除
    elem = queue.pop() # 彈出右邊元素, deque([‘A‘, ‘B‘, ‘C‘, ‘D‘])
    elem = queue.popleft() # 彈出左邊元素, deque([‘B‘, ‘C‘, ‘D‘])
    queue.remove("C") # deque([‘B‘, ‘D‘])
    queue.clear() # 清空


    # 指針
    queue = deque(lists)  # deque([‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘])
    queue.rotate(-1) # 旋轉指針 +元素後移 -元素前移, deque([‘B‘, ‘C‘, ‘D‘, ‘E‘, ‘A‘])

    # 其他
    queue.reverse() # 反轉元素, deque([‘A‘, ‘E‘, ‘D‘, ‘C‘, ‘B‘])
 

Python3-筆記-B-006-數據結構-雙向隊列deque