Add head, tail and thin methods

[griverat]

I feel like there's room for improvement in the docstrings, any change or suggestion is welcome!

• Closes Add head(), tail() and thin() methods? #319
• Tests added
• Passes black . && mypy . && flake8
• Fully documented, including whats-new.rst for all changes and api.rst for new API

[pep8speaks]

Hello @DangoMelon! 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 2019-09-04 19:28:37 UTC

[max-sixty]

Looks great! V good first effort @DangoMelon

Any thoughts from others? Do we want a default (e.g. 5)?

[shoyer]

Do we want to support integer values, indicating that an operation should be applied to all dimensions? e.g., supposing ds has dimensions x and y, then ds.head(5) would be equivalent to ds.head(x=5, y=5).

This would be a natural way to support a default value (if we want that) -- we could simply set the default value to 5, so ds.head() -> ds.head(5) -> ds.head(x=5, y=5).

[shoyer]

But yes, I agree with @max-sixty this looks great, and already ready to merge!

If you don't have time to work on default values and/or integers now, we can always merge this PR now and leave those backwards compatible API changes for later :)

[max-sixty]

Great!

In the spirit of faster iteration, I'll merge this @DangoMelon and then if you want to add default values (I also like the idea of supporting a single value), please go ahead!

[griverat]

Thanks @max-sixty @shoyer !! I also agree with your suggestions and will be working on adding the default values during these days.