CLN: Add typing for dtype argument in codebase

[avinashpancham]

Follow up from #37546 and #38680

Add typing for the dtype argument throughout the pandas codebase. Part of the code might need an update after adding the type since the mypy type checks can fail.

In #38680 it is already done for io/sql.py, from a directory search I found that the list of files below still have untyped dtype arguments.

Would be great if people can work on a few files at a time in separate PRs and mention this issue. I will already start with the remaining files in the io directory

• io/parsers.py
• io/excel/_base.py
• io/json/_json.py
• io/pytables.py
• core/arrays/datetimelike.py
• core/arrays/base.py
• core/arrays/boolean.py
• core/arrays/categorical.py
• core/arrays/integer.py
• core/arrays/interval.py
• core/arrays/masked.py
• core/arrays/numpy_.py
• core/arrays/period.py
• core/arrays/sparse/array.py
• core/arrays/string_.py
• core/arrays/string_arrow.py
• core/arrays/timedeltas.py
• core/indexes/category.py
• core/indexes/datetimes.py
• core/indexes/interval.py
• core/indexes/numeric.py
• core/indexes/period.py
• core/indexes/range.py
• core/internals/block.py
• core/internals/managers.py
• core/reshape/reshape.py
• core/strings/object_array.py
• core/base.py
• core/common.py
• core/frame.py
• core/generic.py
• core/series.py

[avinashpancham]

Add typing for io/parsers.py, io/excel/_base.py, io/json/_json.py and io/pytables.py in 38814

Add typing for core/arrays/datetimelike.py, core/arrays/base.py, core/arrays/boolean.py, core/arrays/categorical.py and core/arrays/integer.py in 38826

[ssooffiiaannee]

I would like to work on a few files, would it be possible?

[avinashpancham]

Sure, go ahead! Would propose to take a number of files (max 5 or less) and start with them. Please first mention the files here such that other people will not work on those files.

[avinashpancham]

I will work on the remainder of files in the directory core/arrays

[avinashpancham]

I will work on all the files in the directory core/indexes and core/strings/object_array.py

[rbpatt2019]

I just submitted an issue (#38948) and a PR (#38968) to add more complete type hints to the pandas.core.frame.dropna method. I'd be happy to tackle the pandas.core.frame module for typing the dtypes argument!

[avinashpancham]

Good to hear! Once you've started, it would be great if you could reference this issue in the PR that will update core/frame.py

[tushushu]

Hi, I would like to work on core/common.py. It seems that no one is working on that yet.

[avinashpancham]

Thanks @tushushu, will mark that file as done.

[avinashpancham]

Will work on the dir core/internals/* and core/reshape/* and the files core/base.py, core/generic.py and core/series.py

[zbremmer]

Anyone working on ```
core/generic.py

[avinashpancham]

Sorry @zbremmer, all the files that need to be modified according to this issue are already taken or finished. But please have a look at other issues, since there are still plenty of open issues!

[avinashpancham]

@rbpatt2019 any updates on core/frame.py, else I will work on it this weekend