Uh oh!
There was an error while loading.Please reload this page.
- Notifications
You must be signed in to change notification settings - Fork32.4k
gh-108751: Add copy.replace() function#108752
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to ourterms of service andprivacy statement. We’ll occasionally send you account related emails.
Already on GitHub?Sign in to your account
Uh oh!
There was an error while loading.Please reload this page.
Conversation
It creates a modified copy of an object by calling the object's__replace__() method.It is a generalization of dataclasses.replace(), named tuple's _replace()method and replace() methods in various classes, and supports all thesestdlib classes.
e0d9d26 to07dd17cCompareDoc/library/copy.rst Outdated
| single: __replace__() (replace protocol) | ||
| Function :func:`replace` is more limited than :func:`copy` and :func:`deepcopy`, | ||
| and only supports named tuples, dataclasses, and other classes which |
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others.Learn more.
| and only supports named tuples,dataclasses, and other classes which | |
| and only supports:term:`named tuples <named tuple>`,:mod:`dataclasses`, and other classes which |
(I haven’t double checked ifnamed tuple ornamedtuple is the right key)
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others.Learn more.
Actually, it does not support named tuples in general. It currently only supports named tuples created bycollections.namedtuple().
| func = getattr(cls, '__replace__', None) | ||
| if func is None: | ||
| raise TypeError(f"replace() does not support {cls.__name__} objects") | ||
| return func(obj, **changes) |
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others.Learn more.
This is a cool feature for very little code!
bedevere-bot commentedSep 6, 2023
There's a new commit after the PR has been approved. @rhettinger: please review the changes made to this pull request. |
This change introduced a regression: see issue#109052. With this change, |
| ---- | ||
| * Add :func:`copy.replace` function which allows to create a modified copy of | ||
| an object, which is especially usefule for immutable objects. |
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others.Learn more.
usefule -> useful
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others.Learn more.
Thanks. Do you mind to create a PR to fix this typo?
Would it make sense to add support for dict? >>>d={'x':1}>>>copy.replace(d,x=2)TypeError:replace()doesnotsupportdictobjects It would be an alternative to: >>>d={'x':1}>>>dict(d,x=2){'x':2}>>> {**d,'x':2}{'x':2} |
Nice feature. |
Perhaps no, because it erodes the difference between an object and a dict (as in JavaScript). And you already have other ways to do this with dicts. |
Uh oh!
There was an error while loading.Please reload this page.
It creates a modified copy of an object by calling the object's
__replace__()method.It is a generalization of dataclasses.replace(), named tuple's _replace() method and replace() methods in various classes, and supports all these stdlib classes.
📚 Documentation preview 📚:https://cpython-previews--108752.org.readthedocs.build/