双向队列
它是一种混合线性数据结构, 涵盖Stack和Queue的全部能力.
# -.- coding:utf-8 -.-
from __future__ import print_function
def checker(func):
def wrapper(self, *args, **kwargs):
if self.empty():
return self.items
return func(self, *args, **kwargs)
return wrapper
class Deque(object):
"""
Deuque: 双向队列
它是一种混合线性数据结构, 涵盖Stack和Queue的全部能力.
"""
def __init__(self):
self.items = []
def size(self):
"""获取栈元素总数."""
return len(self.items)
def empty(self):
"""栈为空则返回: True ; 栈非空返回: False"""
return not self.size()
def append(self, item):
self.items.append(item)
return self.items
def insert(self, item):
self.items.insert(0, item)
return self.items
@checker
def __leftpop(self):
return self.items.pop(0)
@checker
def __rightpop(self):
return self.items.pop(-1)
def get(self):
return self.__leftpop()
def rightget(self):
return self.__rightpop()
@checker
def peek(self):
return self.items[0]
@checker
def rightpeek(self):
return self.items[-1]
def __iter__(self):
return self
def __next__(self):
if not self.empty():
return self.get()
raise StopIteration
def next(self):
return self.__next__()
def __str__(self):
return "{}".format(self.items)
if __name__ == '__main__':
deque = Deque()
# 插入测试数据
deque.append("a")
deque.append("b")
deque.append("c")
deque.insert("x")
deque.insert("y")
deque.insert("z")
# 测试功能
print("查看双向队列: ", deque)
print("获取头元素(不移除元素): ", deque.peek())
print("查看双向队列: ", deque)
print("获取头元素(移除元素): ", deque.get())
print("查看双向队列: ", deque)
print("获取尾元素(不移除元素): ", deque.rightpeek())
print("查看双向队列: ", deque)
print("获取尾元素(移除元素): ", deque.rightget())
print("查看双向队列: ", deque)
# 遍历栈对象
for enum, i in enumerate(deque):
print("遍历第{}个元素: ".format(enum), i)
# 输出结果
# 查看双向队列: ['z', 'y', 'x', 'a', 'b', 'c']
# 获取头元素(不移除元素): z
# 查看双向队列: ['z', 'y', 'x', 'a', 'b', 'c']
# 获取头元素(移除元素): z
# 查看双向队列: ['y', 'x', 'a', 'b', 'c']
# 获取尾元素(不移除元素): c
# 查看双向队列: ['y', 'x', 'a', 'b', 'c']
# 获取尾元素(移除元素): c
# 查看双向队列: ['y', 'x', 'a', 'b']
# 遍历第0个元素: y
# 遍历第1个元素: x
# 遍历第2个元素: a
# 遍历第3个元素: b
