def producer(c):
 n = 0
 while n < 5:
 n += 1
 print('producer {}'.format(n))
 r = c.send(n)
 print('consumer return {}'.format(r))


def consumer():
 r = ''
 while True:
 n = yield r
 if not n:
 return
 print('consumer {} '.format(n))
 r = 'ok'


if __name__ == '__main__':
 c = consumer()
 next(c) # 啟動consumer
 producer(c)

import asyncio

# 定義了一個簡單的協(xié)程
async def simple_async():
 print('hello')
 await asyncio.sleep(1) # 休眠1秒
 print('python')
 
# 使用asynio中run方法運行一個協(xié)程
asyncio.run(simple_async())

# 執(zhí)行結(jié)果為
# hello
# python

# 定義了一個簡單的協(xié)程
async def simple_async():
 print('hello')
 
asyncio.run(simple_async())

# 執(zhí)行結(jié)果
# hello

async def do_something(index):
 print(f'start {time.strftime("%X")}', index)
 await asyncio.sleep(1)
 print(f'finished at {time.strftime("%X")}', index)


def test_do_something():
 # 生成器產(chǎn)生多個協(xié)程對象
 task = [do_something(i) for i in range(5)]

 # 獲取一個事件循環(huán)對象
 loop = asyncio.get_event_loop()
 # 在事件循環(huán)中執(zhí)行task列表
 loop.run_until_complete(asyncio.wait(task))
 loop.close()

test_do_something()

# 運行結(jié)果
# start 00:04:03 3
# start 00:04:03 4
# start 00:04:03 1
# start 00:04:03 2
# start 00:04:03 0
# finished at 00:04:04 3
# finished at 00:04:04 4
# finished at 00:04:04 1
# finished at 00:04:04 2
# finished at 00:04:04 0

await awaitable_object

async def nested():
 print('in nested func')
 return 13


async def outer():

 # 要使用await 關鍵字 才會執(zhí)行一個協(xié)程函數(shù)返回的協(xié)程對象
 print(await nested())

asyncio.run(outer())

# 執(zhí)行結(jié)果
# in nested func
# 13

async def outer():
 # 直接調(diào)用協(xié)程函數(shù)不會發(fā)生執(zhí)行，只是返回一個 coroutine 對象
 nested()
 
asyncio.run(outer())

async def nested():
 print('in nested func')
 return 13

async def create_task():
 # create_task 將一個協(xié)程對象打包成一個 任務時，該協(xié)程就會被自動調(diào)度運行
 task = asyncio.create_task(nested())
 # 如果要看到task的執(zhí)行結(jié)果
 # 可以使用await等待協(xié)程執(zhí)行完成，并返回結(jié)果
 ret = await task
 print(f'nested return {ret}')

asyncio.run(create_task())

# 運行結(jié)果
# in nested func
# nested return 13

async def used_future_func():
 await function_that_returns_a_future_object()

async def do_after(what, delay):
 await asyncio.sleep(delay)
 print(what)

# 利用asyncio.create_task創(chuàng)建并行任務
async def corun():
 task1 = asyncio.create_task(do_after('hello', 1)) # 模擬執(zhí)行1秒的任務
 task2 = asyncio.create_task(do_after('python', 2)) # 模擬執(zhí)行2秒的任務

 print(f'started at {time.strftime("%X")}')
 # 等待兩個任務都完成，兩個任務是并行的，所以總時間兩個任務中最大的執(zhí)行時間
 await task1
 await task2

 print(f'finished at {time.strftime("%X")}')

asyncio.run(corun())

# 運行結(jié)果
# started at 23:41:08
# hello
# python
# finished at 23:41:10

async def do_after(what, delay):
 await asyncio.sleep(delay)
 print(what)
 
async def gather():
 print(f'started at {time.strftime("%X")}')
 # 使用gather可將多個協(xié)程傳入
 await asyncio.gather(
 do_after('hello', 1),
 do_after('python', 2),
 )
 print(f'finished at {time.strftime("%X")}')

asyncio.run(gather())

# 運行結(jié)果
# started at 23:47:50
# hello
# python
# finished at 23:47:52