如何将Python并发和异步编程实例改写为一个长尾词的？

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关于并发、并行、同步阻塞、异步非阻塞、线程、进程、协程等概念，单从文字上理解往往较为困难，难以进行比较深刻的理解。本文将通过代码一步一步实现这些并发和异步编程，便于比较和掌握。

以下是一些基本的并发和异步编程实现示例：

1. 并发编程：使用Python的`threading`模块实现一个简单的并发示例。

pythonimport threading

def print_numbers(): for i in range(1, 6): print(i)

创建线程thread1=threading.Thread(target=print_numbers)thread2=threading.Thread(target=print_numbers)

启动线程thread1.start()thread2.start()

等待线程结束thread1.join()thread2.join()

2. 并行编程：使用Python的`multiprocessing`模块实现一个简单的并行示例。

pythonimport multiprocessing

def print_numbers(): for i in range(1, 6): print(i)

创建进程process1=multiprocessing.Process(target=print_numbers)process2=multiprocessing.Process(target=print_numbers)

启动进程process1.start()process2.start()

等待进程结束process1.join()process2.join()

3. 同步阻塞：使用`threading.Lock`实现线程同步。

pythonimport threading

lock=threading.Lock()

def print_numbers(): for i in range(1, 6): lock.acquire() # 获取锁 print(i) lock.release() # 释放锁

thread1=threading.Thread(target=print_numbers)thread2=threading.Thread(target=print_numbers)

thread1.start()thread2.start()

thread1.join()thread2.join()

4. 异步非阻塞：使用Python的`asyncio`模块实现一个简单的异步示例。

pythonimport asyncio

async def print_numbers(): for i in range(1, 6): print(i)

创建异步任务task=asyncio.create_task(print_numbers())

运行事件循环asyncio.run(task)

通过以上代码示例，我们可以逐步理解并发、并行、同步阻塞、异步非阻塞、线程、进程、协程等概念，并比较它们的异同。

关于并发、并行、同步阻塞、异步非阻塞、线程、进程、协程等这些概念，单纯通过文字恐怕很难有比较深刻的理解，本文就通过代码一步步实现这些并发和异步编程，并进行比较。解释器方面本文选择python3，毕竟python3才是python的未来，并且python3用原生的库实现协程已经非常方便了。

1、准备阶段

下面为所有测试代码所需要的包

#! python3 # coding:utf-8 import socket from concurrent import futures from selectors import DefaultSelector,EVENT_WRITE,EVENT_READ import asyncio import aiowww.sina.com' loop = asyncio.get_event_loop() async def fetch(url): async with aiohttp.ClientSession(loop=loop) as session: async with session.get(url) as response: response = await response.read() return response @tsfunc def asyncio_way(): tasks = [fetch(host+url) for url in urls_todo] loop.run_until_complete(asyncio.gather(*tasks)) return (len(tasks)) @tsfunc def sync_way(): res = [] for i in range(10): res.append(blocking_way()) return len(res) @tsfunc def process_way(): worker = 10 with futures.ProcessPoolExecutor(worker) as executor: futs = {executor.submit(blocking_way) for i in range(10)} return len([fut.result() for fut in futs]) @tsfunc def thread_way(): worker = 10 with futures.ThreadPoolExecutor(worker) as executor: futs = {executor.submit(blocking_way) for i in range(10)} return len([fut.result() for fut in futs]) @tsfunc def async_way(): res = [] for i in range(10): res.append(nonblocking_way()) return len(res) @tsfunc def callback_way(): for url in urls_todo: crawler = Crawler(url) crawler.fetch() loop1() @tsfunc def generate_way(): for url in urls_todo: crawler = Crawler2(url) Task(crawler.fetch()) loop1() if __name__ == '__main__': #sync_way() #process_way() #thread_way() #async_way() #callback_way() #generate_way() asyncio_way()

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