并发——Python篇

** 以下代码均在Python3.5下测试 **

1. 多线程

threading模块实现

import threading, time

class Worker(threading.Thread):
    def __init__(self, num):
        super(Worker,self).__init__()
        self.num = num
    def run(self):
        print("Thread-%d start..." % self.num)
        time.sleep(1)
        print("Thread-%d end..." % self.num)

workers = []
n = 5
st = time.time()
for i in range(n):
    workers.append(Worker(i))
for i in range(n):
    workers[i].start()
for i in range(n):
    workers[i].join()
et = time.time()
print("cost %.3fs" % (et-st))

map实现

from multiprocessing.dummy import Pool
from urllib import request as rq

urls = []
for i in range(100):
    urls.append("http://acm.split.hdu.edu.cn/showproblem.php?pid=%d" % (1000+i))

pool = Pool(5)
pool.map(rq.urlopen, urls)
pool.close()
pool.join()

2. 多进程

import multiprocessing, time

class Worker(multiprocessing.Process):
    def __init__(self, num):
        super(Worker,self).__init__()
        self.num = num
    def run(self):
        print("Process-%d start..." % self.num)
        time.sleep(1)
        print("Process-%d end..." % self.num)

#这句必须写
if __name__ == '__main__':
    workers = []
    n = 5
    st = time.time()
    for i in range(n):
        workers.append(Worker(i))
    for i in range(n):
        workers[i].start()
    for i in range(n):
        workers[i].join()
    et = time.time()
    print("cost %.3fs" % (et-st))

3. 协程

gevent实现

import gevent
from gevent import monkey
from urllib import request as rq
monkey.patch_socket()

urls = []
for i in range(100):
    urls.append("http://acm.split.hdu.edu.cn/showproblem.php?pid=%d" % (1000+i))

def worker(i):
    rq.urlopen(urls[i])

tasks = [gevent.spawn(worker, i) for i in range(100)]
gevent.joinall(tasks)

async/await实现

import asyncio

async def worker():
    await asyncio.sleep(1)

loop = asyncio.get_event_loop()
tasks = [worker() for _ in range(20)]
loop.run_until_complete(asyncio.wait(tasks))
loop.close()