Python 3.4+Async programmingterm

asyncio

module

Asynchronous I/O with async/await: many tasks in a single thread driven by an event loop.

Syntax

import asyncio

It suits work that mostly waits on the network or disk: thousands of connections served by one thread. It does not speed up computation — use processes (concurrent.futures, multiprocessing) for that, and threads for simple waiting with blocking code. A common mistake is calling a blocking function such as time.sleep inside a coroutine: it stalls the whole event loop.

Examples

import asyncio
async def square(n):
    await asyncio.sleep(0)
    return n * n
async def main():
    return await asyncio.gather(square(2), square(3))
print(asyncio.run(main()))  # → [4, 9]

See also

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