day_of_week
- [ ] closes #9606
- [ ] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Hello @Violet-XiaoWeiHuang! Thanks for opening this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:



* In the file [`asv_bench/benchmarks/timestamp.py`](https://github.com/pandas-dev/pandas/blob/e8bf846edb7be90f2dbaa1da7a806b1f9d6e0f82/asv_bench/benchmarks/timestamp.py):

> [Line 50:13](https://github.com/pandas-dev/pandas/blob/e8bf846edb7be90f2dbaa1da7a806b1f9d6e0f82/asv_bench/benchmarks/timestamp.py#L50): [E117](https://duckduckgo.com/?q=pep8%20E117) over-indented









 As mentioned https://github.com/pandas-dev/pandas/pull/25924#issuecomment-478132760, `dayofweek` needs to be deprecated first. This can't just be replaced. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26094?src=pr&el=h1) Report
> Merging [#26094](https://codecov.io/gh/pandas-dev/pandas/pull/26094?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4e7e7f0dd6f60556a2b3abc6078af043302ed852?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26094/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26094?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26094      +/-   ##
==========================================
- Coverage   91.95%   91.94%   -0.01%     
==========================================
  Files         175      175              
  Lines       52443    52445       +2     
==========================================
- Hits        48224    48222       -2     
- Misses       4219     4223       +4
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.5% <100%> (ø)` | :arrow_up: |
| #single | `40.75% <100%> (-0.14%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26094?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9wZXJpb2QucHk=) | `92.04% <ø> (ø)` | :arrow_up: |
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `96.4% <ø> (ø)` | :arrow_up: |
| [pandas/core/arrays/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3BlcmlvZC5weQ==) | `98.54% <100%> (ø)` | :arrow_up: |
| [pandas/core/arrays/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lcy5weQ==) | `97.8% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `75% <0%> (-12.5%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.79% <0%> (-0.12%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26094?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/26094?src=pr&el=footer). Last update [4e7e7f0...e8bf846](https://codecov.io/gh/pandas-dev/pandas/pull/26094?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/26094?src=pr&el=h1) Report
> Merging [#26094](https://codecov.io/gh/pandas-dev/pandas/pull/26094?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4e7e7f0dd6f60556a2b3abc6078af043302ed852?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26094/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26094?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26094      +/-   ##
==========================================
- Coverage   91.95%   91.94%   -0.01%     
==========================================
  Files         175      175              
  Lines       52443    52445       +2     
==========================================
- Hits        48224    48222       -2     
- Misses       4219     4223       +4
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.5% <100%> (ø)` | :arrow_up: |
| #single | `40.75% <100%> (-0.14%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26094?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9wZXJpb2QucHk=) | `92.04% <ø> (ø)` | :arrow_up: |
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `96.4% <ø> (ø)` | :arrow_up: |
| [pandas/core/arrays/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3BlcmlvZC5weQ==) | `98.54% <100%> (ø)` | :arrow_up: |
| [pandas/core/arrays/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lcy5weQ==) | `97.8% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `75% <0%> (-12.5%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26094/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.79% <0%> (-0.12%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26094?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/26094?src=pr&el=footer). Last update [4e7e7f0...e8bf846](https://codecov.io/gh/pandas-dev/pandas/pull/26094?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 can you merge master and update per comments closing as stale. this is pretty close, so ping if you'd like to continue.