Python | AsyncIO | TypeError: a coroutine was expected

Question

I'm trying python coroutine programming using asyncio. This is my code.

import asyncio

async def coro_function():
    return 2 + 2

async def get():
    return await coro_function()

print(asyncio.iscoroutinefunction(get))

loop = asyncio.get_event_loop()
a1 = loop.create_task(get)
loop.run_until_complete(a1)

But when I execute it, it gives me error

True
Traceback (most recent call last):
  File "a.py", line 13, in <module>
    a1 = loop.create_task(get)
  File "/home/alie/anaconda3/lib/python3.7/asyncio/base_events.py", line 405, in create_task
    task = tasks.Task(coro, loop=self)
TypeError: a coroutine was expected, got <function get at 0x7fe1280b6c80>

How to solve it?

Algebra8 · Accepted Answer · 2020-09-20 05:56:30Z

30

You're passing in the function get.

In order to pass in a coroutine, pass in get().

a1 = loop.create_task(get())
loop.run_until_complete(a1)

Take a look at the types:

>>> type(get)
<class 'function'>
>>> print(type(get()))
<class 'coroutine'>

get is a coroutine function, i.e. a function that returns a coroutine object, get(). For more information and a better understanding of the fundamentals, take a look at the docs.

answered Sep 20, 2020 at 5:56

Algebra8

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1 Comment

MickeyDickey on codidact.com Over a year ago

Thanks a lot. Didn't realize python was expecting a call to the function, rather than just the function object itself.

Yablai Bougouyou · Accepted Answer · 2024-11-18 18:50:57Z

1

Here is an example of code that can help you:

import asyncio

sync def coro_function():
        return 2 + 2

def async execute():
    async with asyncio.TaskGroup() as group:
         group.create_task(coro_function())
    
asyncio.run(execute())

edited Nov 18, 2024 at 18:50

answered Nov 18, 2024 at 18:47

Yablai Bougouyou

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1 Comment

mehdi_ahmadi Over a year ago

please read [ How do I write a good answer](stackoverflow.com/help/how-to-answer)

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