What is async for and async with?

Question

Accepted Answer

**async for** iterates over async iterables. **async with** manages async context managers.

```python
import asyncio

# Async iterator
class AsyncCounter:
    def __init__(self, stop):
        self.stop = stop
        self.current = 0

def __aiter__(self):
        return self

async def __anext__(self):
        if self.current >= self.stop:
            raise StopAsyncIteration
        await asyncio.sleep(0.1)  # Simulate async work
        self.current += 1
        return self.current

async def main():
    async for num in AsyncCounter(5):
        print(num)  # 1, 2, 3, 4, 5

asyncio.run(main())
```

**Common use cases:**
- Streaming data from APIs.
- Database cursors.
- File reading (aiofiles).
- Redis/PostgreSQL async iterators.

Python: What is async for and async with?