Add access by column

[laowantong]

Describe your changes

The proposed method ResultSet.column() iterates on a column given by name.

jupysql/src/sql/run/resultset.py

Lines 249 to 256 in 17ab97c

	def column(self, name):
	"""Iterator yielding the values on a column specified by name"""
	try:
	column_index = list(self.keys).index(name)
	except ValueError:
	raise KeyError(f"Column '{name}' not found in the result set")
	for row in self:
	yield row[column_index]

Additions:

• a method column(name) in resultset.py (above);
• a method test_resultset_column(result_set) in test_resultset.py with a successful test and a failed test;
• a paragraph in doc_intro.md;
• an entry in changelog.md.

Checklist before requesting a review

• Performed a self-review of my code
• Formatted my code with pkgmt format
• Added tests (when necessary).
• Added docstring documentation and update the changelog (when needed)

---

📚 Documentation preview 📚: https://jupysql--1002.org.readthedocs.build/en/1002/

[neelasha23]

@laowantong Hey is there a related issue? Please mention the issue number also

[laowantong]

No existing issue. I have just tried to add a feature which I felt was missing for my usage. Not sure why some checks fail. Feel free to close this PR is the procedure is not OK or you think the feature is useless.

[neelasha23]

No existing issue. I have just tried to add a feature which I felt was missing for my usage. Not sure why some checks fail. Feel free to close this PR is the procedure is not OK or you think the feature is useless.

Sure will have a look. There are lint issues in the changes. Please refer to contributing guidelines
Also, do include a description of the changes in the PR description @laowantong

[laowantong]

Sorry for spamming you with my failed attempts to make the checks pass. There are still lint issues, although pkgfmt succeeds on my machine:

$ pkgmt format
Running command:black .
All done! ✨ 🍰 ✨
115 files left unchanged.
Running command:nbqa black .
All done! ✨ 🍰 ✨
56 files left unchanged.
Finished formatting with black!

[neelasha23]

Sorry for spamming you with my failed attempts to make the checks pass. There are still lint issues, although pkgfmt succeeds on my machine:

The lints are passing but the testcase test_resultset_column is failing. @laowantong

[laowantong]

Too much friction for me, sorry. I cannot run the tests on my machine. There are multiple failures everywhere. I give up. You can close this PR. Thanks.