Strictly monotonic

[TomAugspurger]

Closes #16515

I think this can go in 0.20.2, even though part of it is a (small) enhancement.

[TomAugspurger]

#16554

[codecov]

Codecov Report

Merging #16555 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #16555      +/-   ##
==========================================
+ Coverage   90.75%   90.75%   +<.01%     
==========================================
  Files         161      161              
  Lines       51074    51078       +4     
==========================================
+ Hits        46353    46357       +4     
  Misses       4721     4721

Flag	Coverage Δ
#multiple	88.59% <100%> (ø)	⬆️
#single	40.16% <40%> (ø)	⬆️

Impacted Files	Coverage Δ
pandas/core/indexes/base.py	95.75% <100%> (ø)	⬆️
pandas/core/indexes/datetimes.py	95.33% <100%> (ø)	⬆️

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[codecov]

Codecov Report

Merging #16555 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #16555      +/-   ##
==========================================
+ Coverage   90.75%   90.75%   +<.01%     
==========================================
  Files         161      161              
  Lines       51074    51078       +4     
==========================================
+ Hits        46353    46357       +4     
  Misses       4721     4721

Flag	Coverage Δ
#multiple	88.59% <100%> (ø)	⬆️
#single	40.16% <40%> (ø)	⬆️

Impacted Files	Coverage Δ
pandas/core/indexes/datetimes.py	95.33% <100%> (ø)	⬆️
pandas/core/indexes/base.py	95.75% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 03d44f3...dcd38f0. Read the comment docs.

[jorisvandenbossche]

Would dask like to use those is_strictly_monotonic_increasing ? Otherwise keeping them private to not further increase number of methods is also an option.

If we keep public, would put some See also's referring to the other

[jreback]

lgtm. merge away.

[jreback]

thanks!

[jorisvandenbossche]

Asking again, as you merged without responding to my comment: is it needed to add this to the public API? It there demand for this attribute?
If there is not an actual usecase (apart from the internal usage to fix the bug), I would consider making them not public

[TomAugspurger]

I'm slightly in favor of having it public. In terms of cognitive load, this feels like half an additional method, rather than 2 additional methods 😄 Just since these are so similar to is_monotonic_increasing and decreasing in name and functionality.

But happy hide it if you want.

[jorisvandenbossche]

In terms of cognitive load, this feels like half an additional method, rather than 2 additional methods 😄 Just since these are so similar to is_monotonic_increasing

Yes, but in tab completion they don't appear together, so I would say it is back to a full additional method in feeling :-)

Since it is very easy to do this yourself as you said above (just combine it with is_unique), I would rather add that as an example to the docs and leave them private

[TomAugspurger]

Since it is very easy to do this yourself as you said above (just combine it with is_unique), I would rather add that as an example to the docs and leave them private

Perhaps I'm slow, but it took me a day to realize that strictly monotonic = monotonic & unique 😆

PR is at #16576 Let's hide it for now, and if anyone asks for it we can make it public.

[jreback]

@jorisvandenbossche I thought this was fine. yes its a a convience method. Sure you can do it, but why not. ok with re-hiding it as @TomAugspurger PR.