# Can Python use ARC and eliminate GC **URL:** \ **Category:** Python Help\ **Created:** [March 19, 2022, 7:21pm UTC](https://discuss.python.org/t/can-python-use-arc-and-eliminate-gc/14467 "2022-03-19T19:21:51Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![ljh](https://avatars.discourse-cdn.com/v4/letter/l/ecae2f/32.png) [@ljh](https://discuss.python.org/u/ljh)\ **Post date:** [March 19, 2022, 7:21pm UTC](https://discuss.python.org/t/can-python-use-arc-and-eliminate-gc/14467/1 "2022-03-19T19:21:51Z")
Hi forum, I’m wondering why python uses both reference counting and garbage collection. Objective-C and Swift use only [Automatic Reference Counting (ARC)](https://clang.llvm.org/docs/AutomaticReferenceCounting.html) to manage memory usage. Can Python use ARC too and eliminate Garbage Collection? ---
**Author:** ![tim.one](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/tim.one/32/282_2.png) [@tim.one](https://discuss.python.org/u/tim.one)\ **Post date:** [March 19, 2022, 8:24pm UTC](https://discuss.python.org/t/can-python-use-arc-and-eliminate-gc/14467/2 "2022-03-19T20:24:12Z")
> [@ljh](#): > > Objective-C and Swift use only [Automatic Reference Counting (ARC)](https://clang.llvm.org/docs/AutomaticReferenceCounting.html) to manage memory usage. Can Python use ARC too and eliminate Garbage Collection? No. CPython already uses reference counting for the vast bulk of its memory recycling. `gc` is needed in CPython _only_ to reclaim trash in cycles. ARC doesn’t address that at all. Here’s a line from the document you linked to: > It [ARC] does not provide a cycle collector; users must explicitly manage the lifetime of their objects, breaking cycles manually or with weak or unsafe references. ---
**Author:** ![steven.daprano](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/steven.daprano/32/1083_2.png) [@steven.daprano](https://discuss.python.org/u/steven.daprano)\ **Post date:** [March 20, 2022, 12:15am UTC](https://discuss.python.org/t/can-python-use-arc-and-eliminate-gc/14467/3 "2022-03-20T00:15:19Z")
Why do you want to eliminate Python’s garbage collection? Technically, reference counting **is** garbage collection, and CPython has two garbage collectors: the automatic reference counter, and a second gc system for eliminating garbage in cycles. Other Python implementations use different systems: - IronPython uses the .Net garbage collector, whatever that is; - Jython uses the JVM garbage collector, and has no reference counter; - PyPy allows you to choose different garbage collectors at build-time, when you compile the interpreter. Older versions of CPython used only reference counting, and we needed to manage cycles manually. I would not want to go back to those Bad Old Days. ---
**Author:** ![ljh](https://avatars.discourse-cdn.com/v4/letter/l/ecae2f/32.png) [@ljh](https://discuss.python.org/u/ljh)\ **Post date:** [March 20, 2022, 7:05am UTC](https://discuss.python.org/t/can-python-use-arc-and-eliminate-gc/14467/4 "2022-03-20T07:05:43Z")
Thanks Tim, I think ARC does release memory and weak ref is used to stop cycle reference in Swift. I found that `weakref` mentioned in Python too: `cpython/Doc/tutorial/stdlib2.rst`. ---
**Author:** ![ljh](https://avatars.discourse-cdn.com/v4/letter/l/ecae2f/32.png) [@ljh](https://discuss.python.org/u/ljh)\ **Post date:** [March 20, 2022, 7:11am UTC](https://discuss.python.org/t/can-python-use-arc-and-eliminate-gc/14467/5 "2022-03-20T07:11:37Z")
> [@steven.daprano](#): > > Older versions of CPython used only reference counting Thanks Steven, I’m new to Python and did’t know that. > [@steven.daprano](#): > > and we needed to manage cycles manually Do you mean people used weakref to stop cycle reference in their python script code before? ---
**Author:** ![steven.daprano](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/steven.daprano/32/1083_2.png) [@steven.daprano](https://discuss.python.org/u/steven.daprano)\ **Post date:** [March 20, 2022, 2:14pm UTC](https://discuss.python.org/t/can-python-use-arc-and-eliminate-gc/14467/6 "2022-03-20T14:14:42Z")
No, this was before weak references existed. Weak references were added in version 2.1. [https://docs.python.org/2.7/library/weakref.html](https://docs.python.org/2.7/library/weakref.html) The cyclic garbage collector was added in Python 2.0: > **[What's New in Python 2.0](https://web.archive.org/web/20091214142515/http://www.amk.ca/python/2.0)** > > What's New in Python 2.0 so anyone who used Python 1.x had to manage cycles manually. ---
**Author:** ![jeanas](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/jeanas/32/8115_2.png) [@jeanas](https://discuss.python.org/u/jeanas)\ **Post date:** [March 20, 2022, 8:48pm UTC](https://discuss.python.org/t/can-python-use-arc-and-eliminate-gc/14467/7 "2022-03-20T20:48:36Z")
For what it’s worth, you can do ```auto import gc gc.disable() ``` to disable the garbage collector. Then you only have reference counting. That’s mentioned in the `gc` module docs: “Since the collector supplements the reference counting already used in Python, you can disable the collector if you are sure your program does not create reference cycles.” [https://docs.python.org/3/library/gc.html](https://docs.python.org/3/library/gc.html) The drawback is that cycles are no longer collected. If you have a cyclic data structure, you need to either use weak references or “de-cyclicize” your structure when you no longer need it. I guess it could also prevent the interpreter from collecting some of its internal structures, which could contain cycles, though I don’t know about that too much. So, Python without GC is conceptually possible. But it would make Python a vastly different language.