异步（async)

from greenlet import greenletdef func1(): print(10) gr2.switch(6666) # 切换到func2() print(12) gr2.switch()def func2(s): print(9) print(s) gr1.switch() #切换成func1() print(99)gr1 = greenlet(func1)gr2 = greenlet(func2)gr1.switch() #第一步会执行 func1###程序运行后，先打印10，在切换到fun2函数，打印9和666，之后再切换到原函数

def x1(): yield 1 yield from x2() yield 2 #生成器def x2(): yield 3 yield 4f1 = x1()for i in f1: print(i)1342###yield 本质是一个生成器，通过yield from 达到在函数内跳转的目的

@asyncio.coroutinedef x1(): print('9999') yield from asyncio.sleep(2) #遇到IO耗时操作，自动切换到tasks中其他任务 print(2)@asyncio.coroutinedef x2(): print('666') yield from asyncio.sleep(3) print('0000')tasks = [ asyncio.ensure_future(x1()), asyncio.ensure_future(x2())]loop = asyncio.get_event_loop()loop.run_until_complete(asyncio.wait(tasks))999966620000

async def x1(): print('9999') await asyncio.sleep(10) #遇到IO耗时操作，自动切换到tasks中其他任务 print(2)async def x2(): print('666') await asyncio.sleep(11) print('0000')tasks = [ asyncio.ensure_future(x1()), asyncio.ensure_future(x2())]loop = asyncio.get_event_loop()loop.run_until_complete(asyncio.wait(tasks))

任务列表 = 【任务1，任务2....】while True: 可执行任务列表，已完成任务列表 = 【任务列表】 for i in 可执行任务列表： for j in 已完成任务列表 如果 任务列表中 没有可执行任务，则终止循环

loop = asyncio.get_event_loop() # 事件循环loop.run_until_complete(asyncio.wait(任务列表))

async def fun(): print('6666')#创建协程对象，函数内部代码不会执行result = fun() #调用# loop = asyncio.get_event_loop()# loop.run_until_complete(result)asyncio.run(result) #py 3.7 版本，相当于上面2句代码的功能

async def fun(): print('6666') #遇到耗时操作，就去执行第二个函数 await asyncio.sleep(2) print('end') return '返回值'async def func1(): print('执行') response = await fun() print('fun请求结束',response)asyncio.run(func1())执行6666endfun请求结束 返回值

async def x1(): print('1') await asyncio.sleep(2) print('2') return '返回值'async def main(): print('main开始') #创建Task对象，将x1到事件循环taska_list = [ asyncio.create_task(x1()), asyncio.create_task(x1())]print('main结束')done, _ = await asyncio.wait(taska_list)print(done)asyncio.run(main())main开始main结束1122返回值 返

async def set_after(fut): await asyncio.sleep(2) fut.set_result('666')async def main(): # 获取当前事件循环 loop = asyncio.get_running_loop() #创建一个Future对象，没有绑定任何行为，这个任务则不知道什么时候结束 fut = loop.create_future() #创建一个Task,绑定set_after，并在2秒后给fut赋值 #手动设置future任务 await loop.create_task(set_after(fut)) # 等待future对象获取，最终结果，否则一直等下去 data = await fut print(data)asyncio.run(main())

async def x1(): while 1: print('aaa5秒') await asyncio.sleep(5)async def x2(): while 1: print('bbb4秒') await asyncio.sleep(4)async def x3(): print('ccc3秒') await asyncio.sleep(3)def run(): tasks = [] for i in [x1(),x2(),x3()]: tasks.append(asyncio.ensure_future(i)) loop = asyncio.get_event_loop() # 时间循环 loop.run_until_complete(asyncio.wait(tasks))aaa5秒bbb4秒ccc3秒bbb4秒aaa5秒bbb4秒aaa5秒....

class Reader(object): '''自定义异步迭代器''' def __init__(self): self.count = 0 async def readline(self): # await asyncio.sleep(1) self.count +=1 if self.count == 100: return None def __aiter__(self): #返回自身 return self async def __anext__(self): val = await self.readline() #如果为None，则掏出异常 if val == None: raise StopAsyncIteration return val# async for 必须写在协程函数里面async def run(): obj = Reader() async for i in obj: print(i)asyncio.run(run())

class AsyncContextManager: def __init__(self): self.conn = pymysql.connect(host='127.0.0.1',user='root',passwd='root',db = '',port= '',charset='utf8',connect_timeout=10000) async def do_smoething(self): #异步操作数据库 return 666 async def __aenter__(self): self.conn = await asyncio.sleep(1) return self async def __aexit__(self, exc_type, exc_val, exc_tb): #关闭数据库 await asyncio.sleep(1)async def run(): async with AsyncContextManager() as f: result = await f.do_smoething() print(result)asyncio.run(run())

import uvloopasyncio.set_event_loop_policy(uvloop.EventLoopPolicy())

async def execute(adress,password): print('开始执行',adress) # 网络IO操作，链接REDIS redis = await aioredis.create_redis(adress,password=password) # 网络io操作，在redis设置哈希值car,内部在设置3个键值对 #redis = {car:{key1=1,key2=2,key3=3}} await redis.hmset_dict('car',key1=1,key2=2,key3=3) #获取值 result = await redis.hgetall('car',encoding='utf-8') print(result) redis.close() #关闭redis await redis.wait_closed() print('结束',adress)asyncio.run(execute('redis://127.0.0.1:6379',"123456"))

async def execute(host,password): print('开始') conn = await aiomysql.connect(host=host,port=3306,user='root',password=password,db='gungunDb') #获取浮标 cur = await conn.cursor() # await cur.execute("select * from user") # result = await cur.fetchall() print(result) # await cur.close() conn.close() print('结束',host)task_list = [ execute('127.0.0.1','root')]asyncio.run(asyncio.wait(task_list))