Teaching feedback

[davis68]

• I felt like nunique was arbitrarily (re)introduced when it was necessary. It wouldn't be top-of-mind for students solving problems.
• The lesson answers need to be adjacent to the exercises.
• I like the pre-introduction of masks and then circling back around to explain them.
• I feel like Part 4 needs to be broken up and integrated across other lessons: it felt thin on its own.
• Horizontal concatenation felt odd to include.
• The join material is pretty good.
• It'd be good to have an elementary stats module after Part 5 before Part 7, maybe as part of Part 6.
• The actual functions in Part 6 felt contrived: it'd be nicer to take a complicated problem and simplify it but it feels like taking a simple problem (one file) and complicating it (multiple files).

[maxim-belkin]

Thanks for the feedback / criticism, Neal. Marking this as a "good first issue", so that those who want to contribute to the lesson can work on some of the issues you mention above.