GH26139, DOC: Explicit statement of default complevel for HDFStore

[swyoon]

State what None complevel in HDFStore means explicitly.

• closes Doc for HDFStore compression unclear on what the default value of None does #26139

[codecov]

Codecov Report

Merging #26158 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #26158      +/-   ##
==========================================
- Coverage      92%   91.99%   -0.01%     
==========================================
  Files         175      175              
  Lines       52371    52371              
==========================================
- Hits        48184    48180       -4     
- Misses       4187     4191       +4

Flag	Coverage Δ
#multiple	90.55% <ø> (ø)	⬆️
#single	40.74% <ø> (-0.14%)	⬇️

Impacted Files	Coverage Δ
pandas/io/pytables.py	90.22% <ø> (ø)	⬆️
pandas/io/gbq.py	75% <0%> (-12.5%)	⬇️
pandas/core/frame.py	96.9% <0%> (-0.12%)	⬇️

---

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 c79b7bb...6c2b170. Read the comment docs.

[codecov]

Codecov Report

Merging #26158 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #26158      +/-   ##
==========================================
- Coverage   91.98%   91.97%   -0.01%     
==========================================
  Files         175      175              
  Lines       52377    52377              
==========================================
- Hits        48180    48176       -4     
- Misses       4197     4201       +4

Flag	Coverage Δ
#multiple	90.53% <ø> (ø)	⬆️
#single	40.71% <ø> (-0.15%)	⬇️

Impacted Files	Coverage Δ
pandas/io/pytables.py	90.22% <ø> (ø)	⬆️
pandas/io/gbq.py	78.94% <0%> (-10.53%)	⬇️
pandas/core/frame.py	96.9% <0%> (-0.12%)	⬇️

---

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 dc86509...0336076. Read the comment docs.

[gfyoung]

@swyoon : This is looking good! Can you merge / rebase onto master to get the builds green?

[swyoon]

@gfyoung All checks are green.

[gfyoung]

Thanks @swyoon !

As a follow-up, if you would like to change the default from None to 0, that would be great. We might need to deprecate first for that PR.

[swyoon]

@gfyoung My pleasure!

So 1) change defaults to 0, and 2) raise deprecation warning when None value is given.

[gfyoung]

@swyoon : Given that 0 and None are interchangeable, submit the PR with changing the default ONLY. We'll then evaluate if we need to do the deprecation cycle.

[swyoon]

@gfyoung got it.

[jreback]

nothing needs changing here