之前我们使用多线程(threading)和多进程(multiprocessing)完成常规的需求:    在启动的时候start、jon等步骤不能省，复杂的需要还要用1-2个队列。    随着需求越来越复杂，如果没有良好的设计和抽象这部分的功能层次，代码量越多调试的难度就越大。    有没有什么好的方法把这些步骤抽象一下呢，让我们不关注这些细节，轻装上阵呢？答案是：有的，从Python3.2开始一个叫做concurrent.futures被纳入了标准库；而在Python2它属于第三方的futures库，需要手动安装： pip install futuresThe concurrent.futures module provides a high-level interface for asynchronously executing callables.The asynchronous execution can be be performed by threads using ThreadPoolExecutor or seperate processes using ProcessPoolExecutor. Both implement the same interface, which is defined by the abstract Executor class.

import math,timePRIMES = [    112272535095293,    112582705942171,    112272535095293,    115280095190773,    115797848077099,    1099726899285419]def is_prime(n):    if n % 2 == 0:        return False    sqrt_n = int(math.floor(math.sqrt(n)))    for i in range(3, sqrt_n + 1, 2):        if n % i == 0:            return False    return Truedef main():    for num in PRIMES:        print(‘%d is prime: %s‘ % (num, is_prime(num)))if __name__ == ‘__main__‘:    start_time = time.time()    main()    end_time = time.time()    print(‘Run time is %s‘ % (end_time-start_time))---结果---112272535095293 is prime: True112582705942171 is prime: True112272535095293 is prime: True115280095190773 is prime: True115797848077099 is prime: True1099726899285419 is prime: FalseRun time is 3.9570000171661377

import math,timefrom multiprocessing import PoolPRIMES = [    112272535095293,    112582705942171,    112272535095293,    115280095190773,    115797848077099,    1099726899285419]def is_prime(n):    if n % 2 == 0:        return False    sqrt_n = int(math.floor(math.sqrt(n)))    for i in range(3, sqrt_n + 1, 2):        if n % i == 0:            return False    return Truedef main():    pool = Pool()    res_l = []    for prime in PRIMES:        res = pool.apply_async(func=is_prime,args=(prime,))        res_l.append(res)    pool.close()    pool.join()    for number, prime in zip(PRIMES, res_l):        print(‘%d is prime: %s‘ % (number, prime.get()))if __name__ == ‘__main__‘:    start_time = time.time()    main()    end_time = time.time()    print(‘Run time is %s‘ % (end_time-start_time))---结果---112272535095293 is prime: True112582705942171 is prime: True112272535095293 is prime: True115280095190773 is prime: True115797848077099 is prime: True1099726899285419 is prime: FalseRun time is 2.687000036239624

ProcessPoolExecutor uses the multiprocessing module, which allows it to side-step the Global Interpreter Lock but also means that only picklable objects can be executed and returned.class concurrent.futures.ProcessPoolExecutor(max_workers=None)    Executes calls asynchronously using a pool of at most max_workers processes.     If max_workers is None or not given then as many worker processes will be created as the machine has processors.

import math,timefrom concurrent import futuresPRIMES = [    112272535095293,    112582705942171,    112272535095293,    115280095190773,    115797848077099,    1099726899285419]def is_prime(n):    if n % 2 == 0:        return False    sqrt_n = int(math.floor(math.sqrt(n)))    for i in range(3, sqrt_n + 1, 2):        if n % i == 0:            return False    return Truedef main():    with futures.ProcessPoolExecutor() as executor:        for number, prime in zip(PRIMES, executor.map(is_prime, PRIMES)):            print(‘%d is prime: %s‘ % (number, prime))if __name__ == ‘__main__‘:    start_time = time.time()    main()    end_time = time.time()    print(‘Run time is %s‘ % (end_time-start_time))---结果---112272535095293 is prime: True112582705942171 is prime: True112272535095293 is prime: True115280095190773 is prime: True115797848077099 is prime: True1099726899285419 is prime: FalseRun time is 2.482999801635742

The ThreadPoolExecutor class is an Executor subclass that uses a pool of threads to execute calls asynchronously.class concurrent.futures.ThreadPoolExecutor(max_workers)    Executes calls asynchronously using at pool of at most max_workers threads.

import urllib.requestimport timeURLS = [    ‘http://www.foxnews.com/‘,    ‘https://www.stanford.edu/‘,    ‘http://www.mit.edu/‘,    ‘https://www.python.org/‘,    ‘https://www.yahoo.com/‘,    ‘http://www.ox.ac.uk/‘]def load_url(url, timeout):    return urllib.request.urlopen(url, timeout=timeout).read()start_time = time.time()for url in URLS:    print(‘%r page is %d bytes‘ % (url, len(load_url(url,60))))end_time = time.time()print("Run time is %s" % (end_time-start_time))---结果---‘http://www.foxnews.com/‘ page is 71131 bytes‘https://www.stanford.edu/‘ page is 68595 bytes‘http://www.mit.edu/‘ page is 21405 bytes‘https://www.python.org/‘ page is 47701 bytes‘https://www.yahoo.com/‘ page is 434510 bytes‘http://www.ox.ac.uk/‘ page is 93411 bytesRun time is 5.068000078201294

import urllib.requestimport timefrom threading import ThreadURLS = [    ‘http://www.foxnews.com/‘,    ‘https://www.stanford.edu/‘,    ‘http://www.mit.edu/‘,    ‘https://www.python.org/‘,    ‘https://www.yahoo.com/‘,    ‘http://www.ox.ac.uk/‘]def load_url(url, timeout):    res = urllib.request.urlopen(url, timeout=timeout).read()    print(‘%r page is %d bytes‘ % (url, len(res)))t_l = []start_time = time.time()for url in URLS:    t = Thread(target=load_url,args=(url,60,))    t_l.append(t)    t.start()for t in t_l:    t.join()end_time = time.time()print("Run time is %s" % (end_time-start_time))---结果---‘http://www.mit.edu/‘ page is 21403 bytes‘http://www.foxnews.com/‘ page is 71735 bytes‘https://www.python.org/‘ page is 47701 bytes‘https://www.stanford.edu/‘ page is 69130 bytes‘http://www.ox.ac.uk/‘ page is 93411 bytes‘https://www.yahoo.com/‘ page is 446715 bytesRun time is 2.6540000438690186

from concurrent import futuresimport urllib.requestimport timeURLS = [    ‘http://www.foxnews.com/‘,    ‘https://www.stanford.edu/‘,    ‘http://www.mit.edu/‘,    ‘https://www.python.org/‘,    ‘https://www.yahoo.com/‘,    ‘http://www.ox.ac.uk/‘]def load_url(url, timeout):    return urllib.request.urlopen(url, timeout=timeout).read()start_time = time.time()with futures.ThreadPoolExecutor(max_workers=5) as executor:    future_to_url = dict((executor.submit(load_url, url, 60), url) for url in URLS)    for future in futures.as_completed(future_to_url):        url = future_to_url[future]        if future.exception() is not None:            print(‘%r generated an exception: %s‘ % (url,future.exception()))        else:            print(‘%r page is %d bytes‘ % (url, len(future.result())))end_time = time.time()print("Run time is %s" % (end_time-start_time))---结果---‘http://www.mit.edu/‘ page is 21405 bytes‘http://www.foxnews.com/‘ page is 71197 bytes‘https://www.python.org/‘ page is 47701 bytes‘http://www.ox.ac.uk/‘ page is 93411 bytes‘https://www.yahoo.com/‘ page is 444854 bytes‘https://www.stanford.edu/‘ page is 68595 bytesRun time is 2.497999906539917