python-async-patterns

# Python Async Patterns

Master asynchronous programming in Python using asyncio, async/await syntax,
and concurrent execution patterns for I/O-bound and CPU-bound tasks.

## Basic Async/Await

**Core async syntax:**

```python
import asyncio

# Define async function with async def
async def fetch_data(url: str) -> str:
    print(f"Fetching {url}...")
    await asyncio.sleep(1)  # Simulate I/O operation
    return f"Data from {url}"

# Call async function
async def main() -> None:
    result = await fetch_data("https://api.example.com")
    print(result)

# Run async function
asyncio.run(main())
```

**Multiple concurrent operations:**

```python
import asyncio

async def fetch_url(url: str) -> str:
    await asyncio.sleep(1)
    return f"Content from {url}"

async def main() -> None:
    # Run concurrently with gather
    results = await asyncio.gather(
        fetch_url("https://example.com/1"),
        fetch_url("https://example.com/2"),
        fetch_url("https://example.com/3")
    )
    for result in results:
        print(result)

asyncio.run(main())
```

## asyncio.create_task

**Creating and managing tasks:**

```python
import asyncio

async def process_item(item: str, delay: float) -> str:
    await asyncio.sleep(delay)
    return f"Processed {item}"

async def main() -> None:
    # Create tasks for concurrent execution
    task1 = asyncio.create_task(process_item("A", 2.0))
    task2 = asyncio.create_task(process_item("B", 1.0))
    task3 = asyncio.create_task(process_item("C", 1.5))

    # Do other work while tasks run
    print("Tasks started")

    # Wait for tasks to complete
    result1 = await task1
    result2 = await task2
    result3 = await task3

    print(result1, result2, result3)

asyncio.run(main())
```

**Task with name and context:**

```python
import asyncio

async def background_task(name: str) -> None:
    print(f"Task {name} starting")
    await asyncio.sleep(2)
    print(f"Task {name} completed")

async def main() -> None:
    # Crea