PEP 769: Add a 'default' keyword argument to 'attrgetter' and 'itemgetter'

[facundobatista]

Selected number: 769

This PEP is about adding a default keyword argument to attrgetter and itemgetter (from the operator module`).

Thanks!

Basic requirements (all PEP Types)

• Read and followed PEP 1 & PEP 12
• File created from the latest PEP template
• PEP has next available number, & set in filename (pep-NNNN.rst), PR title (PEP 123: <Title of PEP>) and PEP header
• Title clearly, accurately and concisely describes the content in 79 characters or less
• Core dev/PEP editor listed as Author or Sponsor, and formally confirmed their approval
• Author, Status (Draft), Type and Created headers filled out correctly
• PEP-Delegate, Topic, Requires and Replaces headers completed if appropriate
• Required sections included
  • Abstract (first section)
  • Copyright (last section; exact wording from template required)
• Code is well-formatted (PEP 7/PEP 8) and is in code blocks, with the right lexer names if non-Python
• PEP builds with no warnings, pre-commit checks pass and content displays as intended in the rendered HTML
• Authors/sponsor added to .github/CODEOWNERS for the PEP

Standards Track requirements

• PEP topic discussed in a suitable venue with general agreement that a PEP is appropriate
• Suggested sections included (unless not applicable)
  • Motivation
  • Rationale
  • Specification
  • Backwards Compatibility
  • Security Implications
  • How to Teach This
  • Reference Implementation
  • Rejected Ideas
  • Open Issues
• Python-Version set to valid (pre-beta) future Python version, if relevant
• Any project stated in the PEP as supporting/endorsing/benefiting from the PEP formally confirmed such
• Right before or after initial merging, PEP discussion thread created and linked to in Discussions-To and Post-History

---

📚 Documentation preview 📚: https://pep-previews--4179.org.readthedocs.build/pep-0769/

[hugovk]

Hello!

Selected number: 790

You can use 790 if you like, but we normally pick the next one in sequence, which currently would be 769. Would you prefer to use 769?

I've also updated the PR description to include the new PEP checklist, please could you work down it and check them off as appropriate?

Thanks!

[hugovk]

Please could you also wrap lines to 79 columns? https://peps.python.org/pep-0012/#general

If you have prettier installed, this can do it:

prettier --prose-wrap=always --print-width=79 -w filename.rst

[facundobatista]

Hello @hugovk !

Thanks for the help and info.

• I've chosen 790 because the biggest one 0xxx was 0789, I didn't search for gaps. I'm fine with using 769, however I have a question: the branch is named add-pep-790, if I rename it (git branch -m add-pep-769) will we get a new PR? is that ok?

• I wrapped all lines.

• I ticked all the items in the description, except:

  • "PEP has next available number...": I may change the number, see first question above

  • "PEP builds with no warnings": I'm in that process, will confirm when it's done

  • "Reference Implementation": I may include it after first PEP review pass, when we decide on a detail listed in open issues...

  • "Right before or after initial merging, PEP discussion thread created and linked": I'll create it after merge

I'm working now in making all linters go green.

Thanks again for all the help!

[facundobatista]

Linters and builders fixed!

[hugovk]

You're welcome!

• I've chosen 790 because the biggest one 0xxx was 0789, I didn't search for gaps. I'm fine with using 769, however I have a question: the branch is named add-pep-790, if I rename it (git branch -m add-pep-769) will we get a new PR? is that ok?

Let's go for 769 then.

If you make a new branch, you'll need to make a new PR. But the branch name isn't too important and the branch will be deleted after merge, so I'd just keep the current one.

[facundobatista]

Cool, thanks! I renamed it to 769, then. Also updated PR title and description.

Let me know when this is ready for the discussion in the forum, and I'll open a thread there.

Thanks!

[hugovk]

And move this up a few lines:

Suggested change

	peps/pep-0790.rst @facundobatista
	peps/pep-0767.rst @facundobatista

[hugovk]

typo:

Suggested change

	However, this would be not as eficient as we'd want for particular cases,
	However, this would be not as efficient as we'd want for particular cases,

[hugovk]

Suggested change

	About Posible Implementations
	-----------------------------
	About Possible Implementations
	------------------------------

[hugovk]

Suggested change

	retrieve the item with a default. See examples in the About Posible
	Implementations subsection before.
	retrieve the item with a default. See examples in the About Possible
	Implementations subsection above.

Or we could add a reference?

For example, add this above:

+.. _PEP 769 About Possible Implementations:
 
 About Posible Implementations
 -----------------------------

And then:

Suggested change

	retrieve the item with a default. See examples in the About Posible
	Implementations subsection before.
	retrieve the item with a default. See examples in the `About Possible
	Implementations <PEP 769 About Possible Implementations_>`__ subsection above.

[hugovk]

We could add similar reference here if we want to hyperlink it.

[hugovk]

So the following code is shown as code, not blockquote:

Suggested change

	``attrgetter("name", default=XYZ)(obj)`` would be like:
	``attrgetter("name", default=XYZ)(obj)`` would be like::

[hugovk]

This could also be a linked reference.

[hugovk]

Suggested change

	(however see previous open issue about special case for dictionaries)
	(However see previous open issue about special case for dictionaries.)

[facundobatista]

Thanks! There I followed all your suggestions. I'm not 100% sure if the linked sections is fine, Github is not rendering those correctly but I understand that it may be a Github thing not supporting ReST 100% ok.

Thanks again!