Support attribute-based node grouping

[networmix]

Summary

• allow selecting node groups by attribute value using attr: directive
• document attribute directive in network view selection
• test attribute-based grouping for networks and views

Testing

• make format (fails: pre-commit: No such file or directory)
• ruff format ngraph/network.py ngraph/network_view.py tests/test_network_selection.py tests/test_network_view.py
• ruff check ngraph/network.py ngraph/network_view.py tests/test_network_selection.py tests/test_network_view.py --fix
• make docs
• make check (fails: pre-commit is not installed)
• pytest (fails: No module named 'yaml')

---

https://chatgpt.com/codex/tasks/task_e_6894b36acdf0832186d9aed47ad47219

[Copilot]

Pull Request Overview

This PR adds support for selecting and grouping nodes by attribute values using an attr: directive prefix in the select_node_groups_by_path method. This extends the existing regex-based node selection to allow grouping by arbitrary node attributes.

Key changes:

• Added attribute-based node grouping with attr:<name> syntax
• Updated docstrings to document the new directive
• Added comprehensive test coverage for both Network and NetworkView classes

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
ngraph/network.py	Added attribute-based grouping logic and updated docstring
ngraph/network_view.py	Updated docstring to document attribute directive
tests/test_network_selection.py	Added test for attribute-based grouping on Network
tests/test_network_view.py	Added test for attribute-based grouping on NetworkView

[Copilot]

The condition value is not None excludes nodes with explicit None values, which may be valid attribute values. Consider using attr_name in node.attrs to check for attribute existence instead, or document this behavior clearly.

Suggested change

	value = node.attrs.get(attr_name)
	if value is not None:
	if attr_name in node.attrs:
	value = node.attrs[attr_name]