What is Asynchronous Programming?

Asynchronous programming allows a program to handle many tasks concurrently by pausing and resuming functions using async and await. It’s useful for I/O-bound tasks such as web requests or file operations.

Why Use Async Programming?

• Efficient use of I/O operations
• Non-blocking execution
• Better performance in network-heavy apps

Basic async/await Syntax

import asyncio

async def greet():
    print("Hello")
    await asyncio.sleep(1)
    print("World")

asyncio.run(greet())

Running Multiple Tasks Concurrently

import asyncio

async def task(name, delay):
    await asyncio.sleep(delay)
    print(f"Finished {name}")

async def main():
    await asyncio.gather(
        task("A", 1),
        task("B", 2),
        task("C", 1)
    )

asyncio.run(main())

Using async with HTTP Requests (aiohttp)

import aiohttp
import asyncio

async def fetch(url):
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as response:
            return await response.text()

async def main():
    html = await fetch("https://example.com")
    print(html[:100])  # Print first 100 characters

asyncio.run(main())

Difference Between Threading and Async

• Threading: Multiple OS threads; used for I/O or CPU-bound tasks
• Async: Single-threaded, cooperative multitasking; best for I/O-bound operations

When to Use Async

• When making multiple API calls
• When doing non-blocking operations (e.g., disk/network I/O)
• When building real-time apps (chat, streaming, etc.)

Pros and Cons

Conclusion

Python's asynchronous programming using asyncio and await enables writing efficient, concurrent code, particularly for I/O-heavy operations like APIs and file handling. It’s an essential technique for modern Python developers building responsive applications.