with Context manager
Last updated: 2026-09-22
with Context manager
with calls __enter__ / __exit__ on a context manager; common for files, locks, connections.
| Category | Keywords & Statements |
|---|---|
| Kind | Keyword / Statement |
| Python Version | all |
📝 Syntax
with expr [as target]:
block▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
closed: True💡 Tip with is the idiomatic way to manage resources; cleaner than try/finally.
💡 Related Cases
More case studies coming soon — check back later.
❓ FAQ
QAfter opening a file with `with`, do I still need to close it manually?
ANo. `with` automatically calls the file's `close()` (via `__exit__`) when leaving the block, even if an exception is raised midway. This is the officially recommended way to manage resources.
QCan `with` manage several resources at once?
AYes. Python 3.10+ allows `with (open(a) as f1, open(b) as f2):`. On older versions use nested `with`, or manage dynamically with `contextlib.ExitStack`.
QIs the `as` variable after `with` still usable outside the block?
AThe variable name is still accessible (Python has no block-level scoping), but the resource is already closed. For example, reading or writing a file outside the `with` raises `ValueError: I/O operation on closed file`.
