python 队列Queue

Posted 2020-12-05 python|一路向前

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基本FIFO队列：先进先出。

calss Queue.Queue(maxsize=0)

maxsize是个整数，指明了队列中能存放的数据个数的上限。一旦达到上限，插入会导致阻塞，直到队列中的数据被消费掉。

#coding:utf-8
import Queue
q=Queue.Queue(5) #队列中只能存放5个数据
for i in range(5):
    q.put(i)
while not q.empty():
    print q.get()

LIFO队列:后进先出

class Queue.LifoQueue(maxsize=0)

#coding:utf-8
import Queue
q=Queue.LifoQueue(5) #队列中只能存放5个数据
for i in range(5):
    q.put(i)
while not q.empty():
    print q.get()

结果：

4
3
2
1
0

优先级队列

class Queue.PriorityQueue(maxsize=0)

import Queue
import threading

class Job(object):
    def __init__(self, priority, description):
        self.priority = priority
        self.description = description
        print ‘Job:‘,description
        return
    def __cmp__(self, other):
        return cmp(self.priority, other.priority)

q = Queue.PriorityQueue()

q.put(Job(3, ‘level 3 job‘))
q.put(Job(10, ‘level 10 job‘))
q.put(Job(1, ‘level 1 job‘))

def process_job(q):
    while True:
        next_job = q.get()
        print ‘for:‘, next_job.description
        q.task_done()

workers = [threading.Thread(target=process_job, args=(q,)),
        threading.Thread(target=process_job, args=(q,))
        ]

for w in workers:
    w.setDaemon(True)
    w.start()

q.join()