Feat/scatter by size
- [y ] partial solution to (only size_by_variable is handled, not color_by_variable) #16827 
- [y] tests added: scatter_test.py shows an example of use
- [y] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [n] whatsnew entry

Let me know if any changes are needed.
Thanks!
Vincent
Hello @VincentAntoine! Thanks for updating the PR.

 - In the file [`pandas/plotting/_core.py`](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py), following are the PEP8 issues :

> [Line 832:80](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L832): [E501](https://duckduckgo.com/?q=pep8%20E501) line too long (87 > 79 characters)
> [Line 838:80](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L838): [E501](https://duckduckgo.com/?q=pep8%20E501) line too long (82 > 79 characters)
> [Line 840:80](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L840): [E501](https://duckduckgo.com/?q=pep8%20E501) line too long (83 > 79 characters)
> [Line 944:13](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L944): [E122](https://duckduckgo.com/?q=pep8%20E122) continuation line missing indentation or outdented
> [Line 944:20](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L944): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 944:22](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L944): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 945:13](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L945): [E122](https://duckduckgo.com/?q=pep8%20E122) continuation line missing indentation or outdented
> [Line 946:54](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L946): [E225](https://duckduckgo.com/?q=pep8%20E225) missing whitespace around operator
> [Line 947:49](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L947): [E113](https://duckduckgo.com/?q=pep8%20E113) unexpected indentation
> [Line 947:54](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L947): [E225](https://duckduckgo.com/?q=pep8%20E225) missing whitespace around operator
> [Line 948:58](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L948): [E225](https://duckduckgo.com/?q=pep8%20E225) missing whitespace around operator
> [Line 949:13](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L949): [E128](https://duckduckgo.com/?q=pep8%20E128) continuation line under-indented for visual indent
> [Line 949:26](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L949): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 949:28](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L949): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 953:13](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L953): [E122](https://duckduckgo.com/?q=pep8%20E122) continuation line missing indentation or outdented
> [Line 954:13](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L954): [E122](https://duckduckgo.com/?q=pep8%20E122) continuation line missing indentation or outdented
> [Line 955:9](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/plotting/_core.py#L955): [E122](https://duckduckgo.com/?q=pep8%20E122) continuation line missing indentation or outdented

 - In the file [`pandas/tests/plotting/test_frame.py`](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/tests/plotting/test_frame.py), following are the PEP8 issues :

> [Line 1017:31](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/tests/plotting/test_frame.py#L1017): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 1017:33](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/tests/plotting/test_frame.py#L1017): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 1033:37](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/tests/plotting/test_frame.py#L1033): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals
> [Line 1033:39](https://github.com/pandas-dev/pandas/blob/84de8ab4827586e99ac8426d0211f3583689f959/pandas/tests/plotting/test_frame.py#L1033): [E251](https://duckduckgo.com/?q=pep8%20E251) unexpected spaces around keyword / parameter equals



##### Comment last updated on March 24, 2018 at 22:50 Hours UTC # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=h1) Report
> Merging [#17582](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/0e85ca7f5afb26880e81ba6ff3965c8c0f27bbaf?src=pr&el=desc) will **decrease** coverage by `0.07%`.
> The diff coverage is `36.58%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17582/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17582      +/-   ##
==========================================
- Coverage   91.22%   91.14%   -0.08%     
==========================================
  Files         163      163              
  Lines       49625    49664      +39     
==========================================
- Hits        45270    45267       -3     
- Misses       4355     4397      +42
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.93% <36.58%> (-0.06%)` | :arrow_down: |
| #single | `40.17% <12.19%> (-0.09%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/plotting/\_core.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb3JlLnB5) | `80.85% <36.58%> (-1.88%)` | :arrow_down: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.77% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17582?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/17582?src=pr&el=footer). Last update [0e85ca7...895afd8](https://codecov.io/gh/pandas-dev/pandas/pull/17582?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/17582?src=pr&el=h1) Report
> Merging [#17582](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/0e85ca7f5afb26880e81ba6ff3965c8c0f27bbaf?src=pr&el=desc) will **decrease** coverage by `0.07%`.
> The diff coverage is `47.61%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17582/graphs/tree.svg?height=150&src=pr&token=eZ4WkYLtcO&width=650)](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17582      +/-   ##
==========================================
- Coverage   91.22%   91.15%   -0.08%     
==========================================
  Files         163      163              
  Lines       49625    49895     +270     
==========================================
+ Hits        45270    45481     +211     
- Misses       4355     4414      +59
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.95% <47.61%> (-0.04%)` | :arrow_down: |
| #single | `40.22% <14.28%> (-0.04%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/plotting/\_core.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb3JlLnB5) | `80.59% <47.61%> (-2.14%)` | :arrow_down: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/util/\_tester.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvX3Rlc3Rlci5weQ==) | `29.41% <0%> (-9.48%)` | :arrow_down: |
| [pandas/core/accessor.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYWNjZXNzb3IucHk=) | `93.75% <0%> (-6.25%)` | :arrow_down: |
| [pandas/plotting/\_tools.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL190b29scy5weQ==) | `72.92% <0%> (-6.08%)` | :arrow_down: |
| [pandas/core/tools/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvdG9vbHMvZGF0ZXRpbWVzLnB5) | `82.97% <0%> (-2.2%)` | :arrow_down: |
| [pandas/core/indexes/category.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9jYXRlZ29yeS5weQ==) | `97.46% <0%> (-1.09%)` | :arrow_down: |
| [pandas/core/indexes/interval.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9pbnRlcnZhbC5weQ==) | `92.85% <0%> (-0.72%)` | :arrow_down: |
| [pandas/core/common.py](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29tbW9uLnB5) | `91.42% <0%> (-0.56%)` | :arrow_down: |
| ... and [49 more](https://codecov.io/gh/pandas-dev/pandas/pull/17582/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17582?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/17582?src=pr&el=footer). Last update [0e85ca7...84de8ab](https://codecov.io/gh/pandas-dev/pandas/pull/17582?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Hi, can you tell me what's needed here? Shall I do something about the checks that fail? If yes what?
Guidance will be useful for me.
Vincent @VincentAntoine could you add an empty commit to re-trigger the CI? `git commit --allow-empty -m 'trigger-ci'` and then `git push`. That should hopefully resolve the CI failures.

Otherwise, I'm going through this again now, and will probably have some feedback, if you want to wait for that. can you rebase / fixup closing as stale, but if you'd like to keep working, ping and we can reopen Hi! I could not get some time to work on this for some time, I could now start working on it again and finish it if that's OK for you.  @VincentAntoine : Go for it!