我们可以使用代码与程序计数器(Program Counter,即PC)来理解:一个Task就是一段将要运行的代码,PC就是当前Task运行到的位置。 当我们运行asyncio.run(main())时,Python会自动将这个coroutine对象包装成一个Task(记为Task 0)。此时,我们的任务列表长这样: Task 0执行了3次asyncio.create_task(async_hello_world()...
urls = ["http://example.com" for _ in range(10)] # 模拟多个URL async def fetch(session, url): async with session.get(url) as response: return await response.text() async def main(): async with aiohttp.ClientSession() as session: tasks = [fetch(session, url) for url in urls] r...
1. imporimport asyncioimport aiohttpasync def fetch(session, url):async with session.get(url) as response:return await response.text()async def main():async with aiohttp.ClientSession() as session:task1 = asyncio.create_task(fetch(session, "http://example.com/page1"))task2 = asyncio.crea...
async def coroutine_example(): await asyncio.sleep(1) return 1 loop = asyncio.get_event_loop() coro = coroutine_example() task = loop.create_task(coro) print('运行情况:', task) try: print('返回值:', task.result()) except asyncio.InvalidStateError: print('task状态未完成,捕获了 InvalidS...
Example: async def main(): await asyncio.sleep(1) print('hello') asyncio.run(main()) """ asyncio.run()主要做两个事情: 建立event loop,用于调用执行可等待对象 。在一个线程内只能有一个event loop; 2. event loop建立后,将执行协程对象main,待执行完成后返回执行结果。协程对象main是由程序中最高...
asyncio.Task,通常由把协程对象传给asyncio.create_task() 得到。 然而,终端用户编写的代码不一定要使用await 处理Task,还可以使用asyncio.create_task(one_coro()) 调度 one_coro 并发执行,不等待它返回。我们在spinner_async.py 中的 spinner 协程内就是这么做的(见示例19-4)。如果不打算取消或等待任务,则无...
import asyncioasyncdeffetch_data(url): print(f"正在请求 {url}")await asyncio.sleep(2) # 模拟网络请求 print(f"请求完成 {url}")asyncdefmain(): tasks = [ fetch_data("http://example.com"), fetch_data("http://example.org"), fetch_data("http://example.net") ]...
()assession:page1=asyncio.create_task(fetch_async('http://example.com',session))page2=asyncio.create_task(fetch_async('http://example.org',session))awaitasyncio.gather(page1,page2)start_time=time.time()asyncio.run(main())print(f"Done in {time.time() - start_time} seconds")# Output:...
# SuperFastPython.com# example of waiting for all tasks to completefromrandomimportrandomimportasyncio# coroutine to execute in a new taskasyncdeftask_coro(arg):# generate a random value between 0 and 1value = random()# block for a momentawaitasyncio.sleep(value)# report the valueprint(f'>...
()asyncdefmain():urls=['https://www.example.com','https://www.python.org','https://www.github.com']asyncwithaiohttp.ClientSession()assession:tasks=[]forurlinurls:task=asyncio.ensure_future(fetch(session,url))tasks.append(task)responses=awaitasyncio.gather(*tasks)forresponseinresponses:print...