この記事では、Python の concurrent future モジュールについての紹介 (コード) を紹介します。一定の参考値があります。必要な友人は参照してください。お役に立てれば幸いです。
このモジュールの主な機能は、ThreadPoolExecutor クラスと ProcessPoolExecutor クラスです。どちらのクラスも concurrent.futures._base.Executor クラスを継承しています。それらが実装するインターフェイスは使用できます。さまざまな Callable オブジェクトはスレッドまたはプロセスで実行され、それらはすべて内部的にワーカー スレッドまたはプロセス プールを維持します。
ThreadPoolExecutor クラスと ProcessPoolExecutor クラスは高度なクラスであり、ほとんどの場合、実装の詳細に注意を払うことなく、使い方を学ぶだけで十分です。
#ProcessPoolExecutor クラス>class ThreadPoolExecutor(concurrent.futures._base.Executor) >| This is an abstract base class for concrete asynchronous executors. >| Method resolution order: >| ThreadPoolExecutor | concurrent.futures._base.Executor | builtins.object | | Methods defined here: | | init(self, max_workers=None, thread_name_prefix='') | Initializes a new ThreadPoolExecutor instance. | | Args: | max_workers: The maximum number of threads that can be used to | execute the given calls. | thread_name_prefix: An optional name prefix to give our threads. | | shutdown(self, wait=True) | Clean-up the resources associated with the Executor. | | It is safe to call this method several times. Otherwise, no other | methods can be called after this one. | | Args: | wait: If True then shutdown will not return until all running | futures have finished executing and the resources used by the | executor have been reclaimed. | | submit(self, fn, *args, **kwargs) | Submits a callable to be executed with the given arguments. | | Schedules the callable to be executed as fn(*args, **kwargs) and returns | a Future instance representing the execution of the callable. | | Returns: | A Future representing the given call. | | ---------------------------------------------------------------------- | Methods inherited from concurrent.futures._base.Executor: | | enter(self) | | exit(self, exc_type, exc_val, exc_tb) | | map(self, fn, *iterables, timeout=None, chunksize=1) | Returns an iterator equivalent to map(fn, iter). | | Args: | fn: A callable that will take as many arguments as there are | passed iterables. | timeout: The maximum number of seconds to wait. If None, then there | is no limit on the wait time. | chunksize: The size of the chunks the iterable will be broken into | before being passed to a child process. This argument is only | used by ProcessPoolExecutor; it is ignored by | ThreadPoolExecutor. | | Returns: | An iterator equivalent to: map(func, *iterables) but the calls may | be evaluated out-of-order. | | Raises: | TimeoutError: If the entire result iterator could not be generated | before the given timeout. | Exception: If fn(*args) raises for any values.
from concurrent import futures with futures.ProcessPoolExecutor(max_works=3) as executor: executor.map()
class ThreadPoolExecutor(concurrent.futures._base.Executor) | This is an abstract base class for concrete asynchronous executors. | | Method resolution order: | ThreadPoolExecutor | concurrent.futures._base.Executor | builtins.object | | Methods defined here: | | init(self, max_workers=None, thread_name_prefix='') | Initializes a new ThreadPoolExecutor instance. | | Args: | max_workers: The maximum number of threads that can be used to | execute the given calls. | thread_name_prefix: An optional name prefix to give our threads. | | shutdown(self, wait=True) | Clean-up the resources associated with the Executor. | | It is safe to call this method several times. Otherwise, no other | methods can be called after this one. | | Args: | wait: If True then shutdown will not return until all running | futures have finished executing and the resources used by the | executor have been reclaimed. | | submit(self, fn, *args, **kwargs) | Submits a callable to be executed with the given arguments. | | Schedules the callable to be executed as fn(*args, **kwargs) and returns | a Future instance representing the execution of the callable. | | Returns: | A Future representing the given call. | | ---------------------------------------------------------------------- | Methods inherited from concurrent.futures._base.Executor: | | enter(self) | | exit(self, exc_type, exc_val, exc_tb) | | map(self, fn, *iterables, timeout=None, chunksize=1) | Returns an iterator equivalent to map(fn, iter). | | Args: | fn: A callable that will take as many arguments as there are | passed iterables. | timeout: The maximum number of seconds to wait. If None, then there | is no limit on the wait time. | chunksize: The size of the chunks the iterable will be broken into | before being passed to a child process. This argument is only | used by ProcessPoolExecutor; it is ignored by | ThreadPoolExecutor. | | Returns: | An iterator equivalent to: map(func, *iterables) but the calls may | be evaluated out-of-order. | | Raises: | TimeoutError: If the entire result iterator could not be generated | before the given timeout. | Exception: If fn(*args) raises for any values.
from time import sleep, strftime
from concurrent import futures
def display(*args):
print(strftime('[%H:%M:%S]'), end="")
print(*args)
def loiter(n):
msg = '{}loiter({}): doing nothing for {}s'
display(msg.format('\t'*n, n, n))
sleep(n)
msg = '{}loiter({}): done.'
display(msg.format('\t'*n, n))
return n*10
def main():
display('Script starting')
executor = futures.ThreadPoolExecutor(max_workers=3)
results = executor.map(loiter, range(5))
display('results:', results)
display('Waiting for inpidual results:')
for i, result in enumerate(results):
display('result {} : {}'.format(i, result))
if __name__ == '__main__':
main()[20:32:12]Script starting [20:32:12]loiter(0): doing nothing for 0s [20:32:12]loiter(0): done. [20:32:12] loiter(1): doing nothing for 1s [20:32:12] loiter(2): doing nothing for 2s [20:32:12]results: <generator object Executor.map.<locals>.result_iterator at 0x00000246DB21BC50> [20:32:12]Waiting for inpidual results: [20:32:12] loiter(3): doing nothing for 3s [20:32:12]result 0 : 0 [20:32:13] loiter(1): done. [20:32:13] loiter(4): doing nothing for 4s [20:32:13]result 1 : 10 [20:32:14] loiter(2): done. [20:32:14]result 2 : 20 [20:32:15] loiter(3): done. [20:32:15]result 3 : 30 [20:32:17] loiter(4): done. [20:32:17]result 4 : 40
Python がフューチャーを通じて同時実行性の問題を処理する方法の詳細な例
以上がPython の concurrent future モジュールの概要 (コード)の詳細内容です。詳細については、PHP 中国語 Web サイトの他の関連記事を参照してください。
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