ENH: New boundary inputs

[hewittk]

• Ensure all linting tests pass, see here for how to run them
• tests added / passed
• closes ENH: consistency of input args for boundaries #40245
• whatsnew entry

[pep8speaks]

Hello @hewittk! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2021-06-25 03:56:00 UTC

[hewittk]

This pull request makes for more consistency and flexibility of the arguments for series.between and the validate_endpoints method of date_timelike.py which is the underlying method of closed for date_range. The parameters that can be inputted to the methods are either a boolean value or a string value of 'both', 'left', 'right', or 'neither'.

[mzeitlin11]

Thanks for the pr @hewittk! Looks like some unrelated changes crept in - seeing some pip related additions which should be reverted

[hewittk]

Thank you for letting me know @mzeitlin11! The pip files should be deleted now, let me know if there are any unrelated additions still there that I haven't noticed.

[mzeitlin11]

Thank you for letting me know @mzeitlin11! The pip files should be deleted now, let me know if there are any unrelated additions still there that I haven't noticed.

Looks good now. I think codecov is failing - if you added new options to parameters, we need to make sure that they're all tested (and a whatsnew note should be added explaining user-facing changes there are here)

[attack68]

Thanks @hewittk for the PR. I made some comments inline. Some of the changes minght be considered non-controversial, and others we might some input from pandas core devs.

[simonjayhawkins]

Thanks @hewittk docstring validation failure to be resolved before merge, otherwise lgtm

[jreback]

@hewittk can you merge master and fix the doc-string

[jreback]

there is a test failure on this build: https://github.com/pandas-dev/pandas/pull/40628/checks?check_run_id=2909716187
likely need to change the inclusive argument in the test.

[simonjayhawkins]

Thanks @hewittk

[jbrockmendel]

@hewittk want to make a PR enforcing this deprecation?