python / 3.7.2rc1 / all / library-asyncio.html

asyncio — Asynchronous I/O


Hello World!

import asyncio

async def main():
    print('Hello ...')
    await asyncio.sleep(1)
    print('... World!')

# Python 3.7+
asyncio.run(main())

asyncio is a library to write concurrent code using the async/await syntax.

asyncio is used as a foundation for multiple Python asynchronous frameworks that provide high-performance network and web-servers, database connection libraries, distributed task queues, etc.

asyncio is often a perfect fit for IO-bound and high-level structured network code.

asyncio provides a set of high-level APIs to:

Additionally, there are low-level APIs for library and framework developers to:

Reference

Note

The source code for asyncio can be found in Lib/asyncio/ .