python并发编程

一：多线程

#!/usr/bin/env python
# -*- coding: utf_8 -*-

# 1.多线程
from __future__ import print_function
import time
import threading
def say_hi():
    print('halo world')
def main():
    for i in range(5):
        thread = threading.Thread(target=say_hi)
        thread.start()
if __name__ == '__main__':
    stime = int(time.time())
    main()
    etime = int(time.time())

    print('use-time',etime-stime)

二：多线程的并发运行

#!/usr/bin/env python
# -*- coding: utf_8 -*-

# 2.多线程
from __future__ import print_function
import time
import threading
def say_hi():
    time.sleep(1)
    print('halo world')
def main():
    for i in range(5):
        thread = threading.Thread(target=say_hi)
        thread.start()

if __name__ == '__main__':
    stime = int(time.time())
    main()
    etime = int(time.time())
    print('use-time', etime - stime)

三：如何给线程传递参数？

#!/usr/bin/env python
# -*- coding: utf_8 -*-

# 3.多线程传递参数
from __future__ import print_function
import time
import threading
def say_hi(count,name):
    while count > 0:
        print(count,"hello",name)
        count -= 1

def main():
    usernames = ['jacke','bob','lucy','jone','mike']
    for i in range(5):
        thread = threading.Thread(target=say_hi,args=(50,usernames[i]))
        thread.start()

if __name__ == '__main__':
    stime = int(time.time())
    main()
    etime = int(time.time())
    print('use-time', etime - stime)

四：通过继承创建线程

from __future__ import  print_function

import threading

class MyThread (threading.Thread):
    def __init__(self,count,name):
        super(MyThread,self).__init__()
        self.count = count
        self.name  = name

    def run(self):
        while self.count > 0:
            print("hello",self.name)
            self.count -= 1

def main():
    usernames=['jacke','bob','lucy','joe','maike']
    for i in range(5):
        thread = MyThread(50,usernames[i])
        thread.start()

if __name__ == '__main__':
    main()

五：线程同步和互斥锁 保证线程的安全

# 5.线程同步和互斥锁
from __future__ import  print_function
import threading
lock = threading.Lock()
num = 0

def incre(count):
    global  num
    while count>0:
        with lock:
            num += 1
        count -= 1

def main():
    threads = []
    for i in range(10):
        thread = threading.Thread(target=incre,args=(100000,))
        thread.start()
        threads.append(thread)

    for thread in threads:
        thread.join()
    print("expected value is",num)

if __name__ == '__main__':
    main()

六：线程安全队列

# 先进先出 队列
from queue import Queue

q = Queue()

for i in range(10):
    q.put(i)

while not q.empty():
    print(q.get())

# 先进后出队列

from queue import LifoQueue

q = LifoQueue()

for i in range(10):
    q.put(i)

while not q.empty():
    print(q.get())


# 按指定优先级输出
from queue import PriorityQueue


class Job(object):
    def __init__(self, priority, description):
        self.priority = priority
        self.description = description
        print('New job:', description)
        return

    def __lt__(self, other):
        return self.priority < other.priority


q = PriorityQueue()

q.put(Job(5, 'Mid-level job'))
q.put(Job(10, 'Low-level job'))
q.put(Job(1, 'Important job'))

while not q.empty():
    next_job = q.get()
    print('Processing job', next_job.description)

未完待续：

多进程
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