DEPR: deprecate notebook argument in DataFrame.to_html()
- [ ] closes #23820
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Code looks pretty good. Just to clarify since I'm not super familiar with this one, does this serve any purpose from an end user perspective or is it pure cruft? 

Just wondering if we should document the alternatives to this if any > Code looks pretty good. Just to clarify since I'm not super familiar with this one, does this serve any purpose from an end user perspective or is it pure cruft?

I'm not sure of the history. Assuming that it was needed internally but added to a public method. So I don't see it serving any purpose to an end user.

> Just wondering if we should document the alternatives to this if any

The alternative is the `_repr_html_` method. As this is not part of the public API, i'm reluctant to suggest this as an alternative. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=h1) Report
> Merging [#26815](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/e6d27ecbdfd2852be48b76d023e9ec2b07c90c4c?src=pr&el=desc) will **decrease** coverage by `1.41%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26815/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26815      +/-   ##
==========================================
- Coverage   91.86%   90.45%   -1.42%     
==========================================
  Files         179      179              
  Lines       50707    50710       +3     
==========================================
- Hits        46584    45870     -714     
- Misses       4123     4840     +717
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.45% <100%> (ø)` | :arrow_up: |
| #single | `?` | |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.89% <100%> (-0.12%)` | :arrow_down: |
| [pandas/core/computation/pytables.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29tcHV0YXRpb24vcHl0YWJsZXMucHk=) | `62.5% <0%> (-27.75%)` | :arrow_down: |
| [pandas/io/pytables.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3B5dGFibGVzLnB5) | `63.82% <0%> (-26.48%)` | :arrow_down: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `88.88% <0%> (-11.12%)` | :arrow_down: |
| [pandas/core/computation/common.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29tcHV0YXRpb24vY29tbW9uLnB5) | `84.21% <0%> (-5.27%)` | :arrow_down: |
| [pandas/core/computation/expr.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29tcHV0YXRpb24vZXhwci5weQ==) | `94.78% <0%> (-3.03%)` | :arrow_down: |
| [pandas/io/clipboard/clipboards.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2NsaXBib2FyZC9jbGlwYm9hcmRzLnB5) | `31.88% <0%> (-2.9%)` | :arrow_down: |
| [pandas/io/formats/printing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvcHJpbnRpbmcucHk=) | `84.49% <0%> (-1.07%)` | :arrow_down: |
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `96.21% <0%> (-0.17%)` | :arrow_down: |
| [pandas/core/arrays/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2NhdGVnb3JpY2FsLnB5) | `95.8% <0%> (-0.13%)` | :arrow_down: |
| ... and [2 more](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=footer). Last update [e6d27ec...fd23985](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=h1) Report
> :exclamation: No coverage uploaded for pull request base (`master@7b25463`). [Click here to learn what that means](https://docs.codecov.io/docs/error-reference#section-missing-base-commit).
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26815/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##             master   #26815   +/-   ##
=========================================
  Coverage          ?   91.86%           
=========================================
  Files             ?      180           
  Lines             ?    50719           
  Branches          ?        0           
=========================================
  Hits              ?    46593           
  Misses            ?     4126           
  Partials          ?        0
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.45% <100%> (?)` | |
| #single | `41.12% <25%> (?)` | |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26815/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.89% <100%> (ø)` | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=footer). Last update [7b25463...97dd413](https://codecov.io/gh/pandas-dev/pandas/pull/26815?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 > add the deprecation here: #6581

done General question on this - are we adding deprecations to the 1.0.0 release or removing outright? I thought adding deprecations. May be wrong though.

On Fri, Aug 30, 2019 at 9:42 AM William Ayd <notifications@github.com>
wrote:

> General question on this - are we adding deprecations to the 1.0.0 release
> or removing outright?
>
> —
> You are receiving this because you are subscribed to this thread.
> Reply to this email directly, view it on GitHub
> <https://github.com/pandas-dev/pandas/pull/26815?email_source=notifications&email_token=AAKAOITUQYS56WHE4KJFJT3QHEWT5A5CNFSM4HXNVKSKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD5R3JRI#issuecomment-526628037>,
> or mute the thread
> <https://github.com/notifications/unsubscribe-auth/AAKAOIWJS5BOXZNVFF7I4OLQHEWT5ANCNFSM4HXNVKSA>
> .
>
 This deprecation docs / warning should have some indication for what users should do instead. What do we recommend? > This deprecation docs / warning should have some indication for what users should do instead. What do we recommend?

there would be no replacement from an end user perspective. see https://github.com/pandas-dev/pandas/pull/26815#issuecomment-501402253 So you're saying it's not useful to users? How do you know that?

Why don't we document what `notebook=True` used to imply? Or, alternatively,
we could just say `_repr_html_` is part of the API for this purpose. It's a
well established
interface that we aren't going to remove.


On Fri, Sep 6, 2019 at 3:20 AM Simon Hawkins <notifications@github.com>
wrote:

> This deprecation docs / warning should have some indication for what users
> should do instead. What do we recommend?
>
> there would be no replacement from an end user perspective. see #26815
> (comment)
> <https://github.com/pandas-dev/pandas/pull/26815#issuecomment-501402253>
>
> —
> You are receiving this because you were mentioned.
> Reply to this email directly, view it on GitHub
> <https://github.com/pandas-dev/pandas/pull/26815?email_source=notifications&email_token=AAKAOIWZXQI3LAV3AFES7G3QIIHEFA5CNFSM4HXNVKSKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD6CD7AY#issuecomment-528760707>,
> or mute the thread
> <https://github.com/notifications/unsubscribe-auth/AAKAOIWXDTAIVOAO3L6WSY3QIIHEFANCNFSM4HXNVKSA>
> .
>
 @simonjayhawkins can you summarize status here there is not agreement that this should be deprecated. so will close and maybe reopen in the future if there is a stronger argument for deprecation.