Python Async

Python Async

July 30, 2020 | python, programming

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Important keywords #

Asynchronous IO (async IO) Language-agnostic paradigm (model)
coroutine A Python (sort of generator function)
async/await Python keywords used to defined a coroutine
asyncio Python package that provides an API for running/managing coroutines

Coroutine #

A coroutine allows a function to pause before returning or indirectly call another coroutine for some time, for example:

import asyncio
import time

async def count(n):
    print(f"n is {n}")
    await asyncio.sleep(n)
    print(f"Returning from {n}")


async def main():
    await asyncio.gather(count(1), count(2), count(3))


m = time.perf_counter()
asyncio.run(main())
elapsed = time.perf_counter() - m

print(f"Executed in {elapsed:0.2f} seconds.")

n is 1
n is 2
n is 3
Returning from 1
Returning from 2
Returning from 3
Executed in 3.00 seconds.

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