deque的应用，实现用户的历史记录

前奏

>>> from collections import deque

>>> q = deque([],5)  #定义一个初值为空列表，最大长度为5的队列

>>> q

deque([], maxlen=5)

>>> q.append(1)

>>> q

deque([1], maxlen=5)

>>> q.append(2)

>>> q.append(3)

>>> q.append(4)

>>> q.append(5)

>>> q

deque([1, 2, 3, 4, 5], maxlen=5)

>>> q.append(6)

>>> q

deque([2, 3, 4, 5, 6], maxlen=5)

 

>>> import pickle

>>> pickle.dump(q, open('history','w')) #将上述队列q序列化至本地文件

>>> q2 = pickle.load(open('history')) #反序列化文件history的内容至内存

>>> q2

deque([2, 3, 4, 5, 6], maxlen=5)

 

---

猜数游戏小程序，有历史记录功能，显示最近猜过的数字

from random import randint
from collections import deque

N = randint(0,100)
history = deque([],5)

def guess(K):
    if K == N:
        print 'right'
        return True
    if K < N:
        print '%s is less' % K
    else:
        print '%s is greater' % K
    return False

while True:
    line = raw_input("please input a number: ") #阻塞
    if line.isdigit():
        K = int(line)
        history.append(K) #添加历史记录
        if guess(K):
            break
    elif line == 'history' or line == 'h?': #定义打印历史记录的命令
        print list(history)

如果历史记录需要保存至本地，请参见前奏的序列化

 

显示运行结果：

please input a number: 55

55 is less

please input a number: 57

57 is less

please input a number: 77

77 is less

please input a number: 80

80 is less

please input a number: 90

90 is greater

please input a number: h?

[55, 57, 77, 80, 90]

please input a number: 85

85 is greater

please input a number: 84

84 is greater

please input a number: h?

[77, 80, 90, 85, 84]

please input a number: 83

83 is greater

please input a number: 82

right