DOC Trying to improve Group by split-apply-combine guide

[DeaMariaLeon]

• closes #xxxx (Replace xxxx with the GitHub issue number)
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

Group by - split-apply-combine.pdf

My aim was to make it easier for the reader. I removed some grammar errors, and tried to cut the lenght of very long sentences.

Also:

• Ln: 46 The word "apply" doesn't make sense to me. I think that it's an error - but I need a reviewer to confirm please.
• Ln: 78 Removed "pandas objects can be split on any of their axes" - I think this needs to be removed because group_by axis=1 was deprecated. But again, it needs to be checked.
• Ln: 102 Same, I thought "axis labels" was not correct because of my previous comment.
• Ln: 272 I'm not sure what you mean. Is "tab" supposed to work on vscode? or on ipython?
• Ln: 364 Trying to cut the long sentence.

I wrote that I was going to do this on PR #51704.

[topper-123]

English is not my native language, so I' a bit unsure of some of the phrases, maybe someone with better english skills can review. I've commented on some of the technical changes.

[rhshadrach]

Thanks for the PR - lots of good changes here. Some questions / requests.

[rhshadrach]

lgtm

[DeaMariaLeon]

Thanks a lot @rhshadrach and @topper-123 for reviewing this PR

[rhshadrach]

/preview

[github-actions]

Website preview of this PR available at: https://pandas.pydata.org/preview/51916/

[rhshadrach]

Thanks @DeaMariaLeon!

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout 2.0.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 c73c1c8cc34fded44e4262596f0f82631628e8b1

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am 'Backport PR #51916: DOC Trying to improve Group by split-apply-combine guide'

4. Push to a named branch:

git push YOURFORK 2.0.x:auto-backport-of-pr-51916-on-2.0.x

5. Create a PR against branch 2.0.x, I would have named this PR:

"Backport PR #51916 on branch 2.0.x (DOC Trying to improve Group by split-apply-combine guide)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.

[rhshadrach]

When I tagged this as 2.0, I was thinking it'd be fine to ship with the 2.0 release since it's just docs in the user guide. However, looking at the conflicts, I now realize that part of this update includes the axis=1 deprecation which will only be in 2.1. So I think we should not backport this.

I've removed the tag, but pinging people to make sure this doesn't mess anything else up. cc @datapythonista @simonjayhawkins

[datapythonista]

Thanks for the ping. Sounds good to me, since no backport PR has been created/merged I think the original milestone shouldn't affect anything, all good.