Promise all in Python

By Thomas Taylor | | 1 minutes
python

In JavaScript, promise.all() returns a single promise given an iterable of promises. The returned promise is fulfilled when all the iterable promises are fulfilled. If one promise is rejected, the resulting promise is also rejected.

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try {
  const values = await Promise.all([promise1, promise2]);
  console.log(values); // [resolvedValue1, resolvedValue2]
} catch (err) {
  console.log(error); // rejectReason of any first rejected promise
}

How to use promise.all() in Python

Python natively supports similar functionality to promise.all(). The method is named asyncio.gather().

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import asyncio

async def some_function():
	await asyncio.sleep(1)
	return 1

async def main():
    values = await asyncio.gather(
        some_function(),
        some_function()
    )
    print(values) # [1, 1]

asyncio.run(main())