REF: DatetimeLikeArray #24024
n.b.: right now I have a few other PRs in this branch (#23601, #23990, #24023). The eventual diff is at TomAugspurger/pandas@disown-tz-only-target...TomAugspurger:disown-tz-only-rebased.
Also, I would say this isn't quite ready for review yet, but I've been promising it for a while. I'm going to try to split off a bit more into separate PRs.
This implements DatetimeArray and TimedeltaArray, arrays for storing datetime
Everything here applies equally to TimedeltaIndex / TimedeltaArray, other than
DatetimeIndex's data is now a DatetimeArray, rather than an ndarray, and its dtype
Class Hierarchy: We've split DatetimeIndex to compose a DatetimeArray,
Internals I've mostly given up here... Things are basically as they were
Types of changes
lightly modified http://www.phyast.pitt.edu/~micheles/python/drawMRO.html