Fragments of Data Cleaning Chapter

[tillahoffmann]

This PR adds the first few sections of the Data Cleaning chapter; it replaces #7. Specifically,

• 01-intro.md containing a brief overview and learning objectives.
• 02-reshaping-data.md discussing long and wide data and transposition.
• 03-tidying-data.md discussing row and column filtering, summary statistics, grouping, sorting, etc.
• Makefile that builds html versions of the markdown documents including execution. We won't need this to present the course, but it's a nice sanity check that the code in the notebooks actually runs.
• requirements.in and requirements.txt which specified the versions of various python packages to avoid runtime environment drift.
• .github/workflows/python-markdown.yml which sets up a python environment and executes the notebooks in CI. I may need a few iterations to get it to build; sorry about the inbox noise.

A few notes:

• I've stuck the files in a folder for the chapter to keep things organized and used .md extensions because the content isn't R. I don't know if that messes with the ottr build?
• Thought I'd get your input on the first few sections of the chapter before committing to the remaining sections. All input welcome!
• I've omitted the "What is Tidy Data?" section because it's not Python-specific and already well covered in the existing course.

[github-actions]

No broken urls! 🎉
Comment updated at 2024-02-22 with changes from 2a68365

[github-actions]

No spelling errors! 🎉
Comment updated at 2024-06-26-03:02:57 with changes from 372ac11

[github-actions]

Re-rendered previews from the latest commit:

• See preview of Bookdown here
• See preview of Coursera/Leanpub version here
• Download the preview of .docx file

Updated at 2024-06-26 with changes from 372ac11

[tillahoffmann]

Converted to draft for now. Will rebase and reopen once #13 is merged.

[cansavvy]

Once you get the branches sorted out, I think the content that is here so far looks great! Very excited for this. Only some minor comments, but the general strategies and content look great to me!

[tillahoffmann]

Thank you for the review! A few follow-up questions inline.

[github-actions]

No broken url errors! 🎉
Comment updated at 2024-06-26-03:02:56 with changes from 372ac11

[tillahoffmann]

Thanks for the review, @davonperson!

I have updated the example dataset to use billboard charts rather than the survey on religion and income. I had to make a few changes to the dictionary and renamed LICENSE.md to LICENSE.txt so it wouldn't get picked up by the spellchecker. Sorry about the commit noise; my editor removed a bunch of trailing spaces when I fixed a broken URL. I think this is now ready to be merged.