import asyncio
import time
async def a():
 print('Suspending a')
 await asyncio.sleep(3)
 print('Resuming a')
async def b():
 print('Suspending b')
 await asyncio.sleep(1)
 print('Resuming b')
async def main():
 start = time.perf_counter()
 await asyncio.gather(a(), b())
 print(f'{main.__name__} Cost: {time.perf_counter() - start}')
if __name__ == '__main__':
 asyncio.run(main())

>>> import asyncio
>>> def fun():
...  print("inner fun")
...  return 111
... 
>>> loop = asyncio.get_event_loop()
>>> future = loop.run_in_executor(None, fun) #這里沒有使用await
inner fun
>>> future #可以看到，fun方法狀態(tài)是pending
<Future pending cb=[_chain_future.<locals>._call_check_cancel() at /usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/asyncio/futures.py:348]>
>>> future.done() # 還沒有完成
False
>>> [m for m in dir(future) if not m.startswith('_')]
['add_done_callback', 'cancel', 'cancelled', 'done', 'exception', 'get_loop', 'remove_done_callback', 'result', 'set_exception', 'set_result']
>>> future.result() #這個時候如果直接調用result()方法會報錯
Traceback (most recent call last):
 File "<input>", line 1, in <module>
asyncio.base_futures.InvalidStateError: Result is not set.
>>> async def runfun():
...  result=await future
...  print(result)
...  
>>>loop.run_until_complete(runfun()) #也可以通過 loop.run_until_complete(future) 來執(zhí)行，這里只是為了演示await
111
>>> future
<Future finished result=111>
>>> future.done()
True
>>> future.result()
111
Task

>>> async def a():
...  print('Suspending a')
...  await asyncio.sleep(3)
...  print('Resuming a')
...  
>>> task = asyncio.ensure_future(a())
>>> loop.run_until_complete(task)
Suspending a
Resuming a

>>> import asyncio
>>> async def a():
...  print('Suspending a')
...  await asyncio.sleep(3)
...  print('Resuming a')
...  return 'A'
... 
... 
... async def b():
...  print('Suspending b')
...  await asyncio.sleep(1)
...  print('Resuming b')
...  return 'B'
... 
>>> async def fun1():
...  return_value_a, return_value_b = await asyncio.gather(a(), b())
...  print(return_value_a,return_value_b)
...  
>>> asyncio.run(fun1())
Suspending a
Suspending b
Resuming b
Resuming a
A B
>>> async def fun2():
...  done,pending=await asyncio.wait([a(),b()])
...  print(done)
...  print(pending)
...  task=list(done)[0]
...  print(task)
...  print(task.result())
...  
>>> asyncio.run(fun2())
Suspending b
Suspending a
Resuming b
Resuming a
{<Task finished coro=<a() done, defined at <input>:1> result='A'>, <Task finished coro=<b() done, defined at <input>:8> result='B'>}
set()
<Task finished coro=<a() done, defined at <input>:1> result='A'>
A

>>> async def fun2():
...  done,pending=await asyncio.wait([a(),b()],return_when=asyncio.tasks.FIRST_COMPLETED)
...  print(done)
...  print(pending)
...  task=list(done)[0]
...  print(task)
...  print(task.result())
...  
>>> asyncio.run(fun2())
Suspending a
Suspending b
Resuming b
{<Task finished coro=<b() done, defined at <input>:8> result='B'>}
{<Task pending coro=<a() running at <input>:3> wait_for=<Future pending cb=[<TaskWakeupMethWrapper object at 0x10757bf18>()]>>}
<Task finished coro=<b() done, defined at <input>:8> result='B'>
B

def callback(future):
 print(f'Result: {future.result()}')
def callback2(future, n):
 print(f'Result: {future.result()}, N: {n}')
async def funa():
 await asyncio.sleep(1)
 return "funa"
async def main():
 task = asyncio.create_task(funa())
 task.add_done_callback(callback)
 await task
 #這樣可以為callback傳遞參數(shù)
 task = asyncio.create_task(funa())
 task.add_done_callback(functools.partial(callback2, n=1))
 await task
if __name__ == '__main__':
 asyncio.run(main())

def a1():
 time.sleep(1)
 return "A"
async def b1():
 await asyncio.sleep(1)
 return "B"
async def main():
 loop = asyncio.get_running_loop()
 await asyncio.gather(loop.run_in_executor(None, a1), b1())
if __name__ == '__main__':
 start = time.perf_counter()
 asyncio.run(main())
 print(f'main method Cost: {time.perf_counter() - start}')
# 輸出： main method Cost: 1.0050589740000002