2021年的原生Python异步调用方式，Python 3.9也适用于Jupyter / Ipython内核

Camabeh的答案是从Python 3.3开始的。

异步def display_date(循环): End_time = loop.time() + 5.0 而真正的: print (datetime.datetime.now ()) If (loop.time() + 1.0) >= end_time: 打破 等待asyncio.sleep (1) Loop = asyncio.get_event_loop() #阻塞调用，当display_date()协程完成时返回 loop.run_until_complete (display_date(循环) loop.close ()

这将在Jupyter笔记本/ Jupyter实验室工作，但抛出一个错误:

RuntimeError: This event loop is already running

由于Ipython使用事件循环，我们需要一些嵌套异步循环，这在Python中还没有实现。幸运的是，有nest_asyncio来处理这个问题。你所需要做的就是:

!pip install nest_asyncio # use ! within Jupyter Notebook, else pip install in shell
import nest_asyncio
nest_asyncio.apply()

(基于此线程)

只有在调用loop.close()时，它才会抛出另一个错误，因为它可能指向Ipython的主循环。

RuntimeError: Cannot close a running event loop

一旦有人回答了这个github问题，我就会更新这个答案。

我的解决方案是:

import threading

class TimeoutError(RuntimeError):
    pass

class AsyncCall(object):
    def __init__(self, fnc, callback = None):
        self.Callable = fnc
        self.Callback = callback

    def __call__(self, *args, **kwargs):
        self.Thread = threading.Thread(target = self.run, name = self.Callable.__name__, args = args, kwargs = kwargs)
        self.Thread.start()
        return self

    def wait(self, timeout = None):
        self.Thread.join(timeout)
        if self.Thread.isAlive():
            raise TimeoutError()
        else:
            return self.Result

    def run(self, *args, **kwargs):
        self.Result = self.Callable(*args, **kwargs)
        if self.Callback:
            self.Callback(self.Result)

class AsyncMethod(object):
    def __init__(self, fnc, callback=None):
        self.Callable = fnc
        self.Callback = callback

    def __call__(self, *args, **kwargs):
        return AsyncCall(self.Callable, self.Callback)(*args, **kwargs)

def Async(fnc = None, callback = None):
    if fnc == None:
        def AddAsyncCallback(fnc):
            return AsyncMethod(fnc, callback)
        return AddAsyncCallback
    else:
        return AsyncMethod(fnc, callback)

并完全按要求工作:

@Async
def fnc():
    pass

你可以使用过程。如果你想永远运行它，在你的函数中使用while(比如networking):

from multiprocessing import Process
def foo():
    while 1:
        # Do something

p = Process(target = foo)
p.start()

如果你只想运行一次，可以这样做:

from multiprocessing import Process
def foo():
    # Do something

p = Process(target = foo)
p.start()
p.join()

Just

import threading, time

def f():
    print "f started"
    time.sleep(3)
    print "f finished"

threading.Thread(target=f).start()

你可以使用并发。期货(在Python 3.2中添加)。

import time
from concurrent.futures import ThreadPoolExecutor


def long_computation(duration):
    for x in range(0, duration):
        print(x)
        time.sleep(1)
    return duration * 2


print('Use polling')
with ThreadPoolExecutor(max_workers=1) as executor:
    future = executor.submit(long_computation, 5)
    while not future.done():
        print('waiting...')
        time.sleep(0.5)

    print(future.result())

print('Use callback')
executor = ThreadPoolExecutor(max_workers=1)
future = executor.submit(long_computation, 5)
future.add_done_callback(lambda f: print(f.result()))

print('waiting for callback')

executor.shutdown(False)  # non-blocking

print('shutdown invoked')

这对我来说很有用，你可以调用这个函数，它会把自己分派到一个新的线程上。

from thread import start_new_thread

def dowork(asynchronous=True):
    if asynchronous:
        args = (False)
        start_new_thread(dowork,args) #Call itself on a new thread.
    else:
        while True:
            #do something...
            time.sleep(60) #sleep for a minute
    return