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????concurrent.futures模塊提供了一個(gè)異步執(zhí)行callables的高級(jí)接口。 可以使用ThreadPoolExecutor和ProcessPoolExecutor。 兩者都繼承了相同的接口，該接口由抽象的Executor類定義。

????一個(gè)抽象類，提供異步執(zhí)行調(diào)用的方法。 它不應(yīng)該直接使用，而是通過其具體的子類。

? ? submit (fn,?*args,?**kwargs)：提交執(zhí)行的函數(shù)并獲取一個(gè)Future對(duì)象，例如：

with ThreadPoolExecutor(max_workers=1) as executor:future = executor.submit(pow, 323, 1235)print(future.result())

????ThreadPoolExecutor：是Executor子類，它使用一個(gè)線程池來異步執(zhí)行調(diào)用。concurrent.futures.ThreadPoolExecutor(max_workers=None,?thread_name_prefix='',?initializer=None,?initargs=())。例如：

import concurrent.futures import urllib.request URLS = ['http://www.foxnews.com/','http://www.cnn.com/','http://europe.wsj.com/','http://www.bbc.co.uk/','http://some-made-up-domain.com/']# Retrieve a single page and report the URL and contents def load_url(url, timeout):with urllib.request.urlopen(url, timeout=timeout) as conn:return conn.read()# We can use a with statement to ensure threads are cleaned up promptly with concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor:# Start the load operations and mark each future with its URLfuture_to_url = {executor.submit(load_url, url, 60): url for url in URLS}for future in concurrent.futures.as_completed(future_to_url):url = future_to_url[future]try:data = future.result()except Exception as exc:print('%r generated an exception: %s' % (url, exc))else:print('%r page is %d bytes' % (url, len(data)))

????ProcessPoolExecutor：concurrent.futures.ProcessPoolExecutor(max_workers=None,?mp_context=None,?initializer=None,?initargs=())：使用如下：

import concurrent.futures import math executor = ProcessPoolExecutor(max_workers=5)def is_prime(n):if n % 2 == 0:return Falsesqrt_n = int(math.floor(math.sqrt(n)))for i in range(3, sqrt_n + 1, 2):if n % i == 0:return Falsereturn Truedef main():for i in range(10): ????????future = executor.submit(is_prime, n)if __name__ == '__main__':main()

????Future: Future類封裝了可調(diào)用的異步執(zhí)行。 該實(shí)例由Executor.submit（）創(chuàng)建。

轉(zhuǎn)載于:https://my.oschina.net/u/3316387/blog/2996178

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