Async / Await

Python · Advanced

Definition

asyncio runs many I/O tasks concurrently in one thread using coroutines with async and await.

Speeds up network-heavy programs like scrapers and APIs.

Diagram

Flowchart

Example: Concurrent tasks

import asyncio
async def job(n):
    await asyncio.sleep(0.01)
    return n * 2
async def main():
    print(await asyncio.gather(job(1), job(2), job(3)))
asyncio.run(main())

Output: [2, 4, 6]

Key points

Great for I/O, not CPU work
Use multiprocessing for CPU-bound tasks

Interview questions

Threading vs asyncio?

Threads are OS-scheduled; asyncio switches cooperatively at await points.