Python await

The await keyword pauses the execution of an asynchronous function until the awaited coroutine, task, or awaitable object completes. It lets asynchronous code read and behave more like synchronous code.

Syntax

await expression

Note: The await keyword can only be used inside an async function. Using it outside an async function will raise a SyntaxError.

Example 1

This example pauses execution while waiting for simulated data to be fetched:

import asyncio

async def fetch_data():
  print("Fetching data...")
  await asyncio.sleep(1)
  print("Data received!")
  return {"data": 42}

async def main():
  result = await fetch_data()
  print("Result:", result)

asyncio.run(main())

Copy to clipboard
Copy to clipboard

Here is the output:

Fetching data...
Data received!
Result: {'data': 42}

Copy to clipboard
Copy to clipboard

In this example:

• async defines an asynchronous function that can contain await.
• asyncio provides tools for running asynchronous code, such as event loops, coroutines, and tasks.

Example 2

This example waits for one second before returning and printing a message:

import asyncio

async def greet():
  await asyncio.sleep(1)
  return "Hello from await!"

async def main():
  message = await greet()
  print(message)

asyncio.run(main())

Copy to clipboard
Copy to clipboard

The output of this code is:

Hello from await!

Copy to clipboard
Copy to clipboard