CSV header default=None
State: closed

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


Labels:
name: Docs
name: IO CSV
description: read_csv, to_csv

Comments:
@Giftlin : Thanks for the PR!  I'm curious: why are you changing this?  The current default is in fact `infer`.
It's a misunderstanding. Closing the PR
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=h1) Report
> Merging [#17549](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/328c7e179b72e257e27adf92a06718fd5a40473f?src=pr&el=desc) will **decrease** coverage by `0.04%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17549/graphs/tree.svg?token=eZ4WkYLtcO&src=pr&height=150&width=650)](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17549      +/-   ##
==========================================
- Coverage   91.25%    91.2%   -0.05%     
==========================================
  Files         163      163              
  Lines       49606    49606              
==========================================
- Hits        45266    45245      -21     
- Misses       4340     4361      +21
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.99% <ø> (-0.03%)` | :arrow_down: |
| #single | `40.19% <ø> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `63.23% <0%> (-1.82%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17549?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/17549?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/17549?src=pr&el=footer). Last update [328c7e1...e62515f](https://codecov.io/gh/pandas-dev/pandas/pull/17549?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/17549?src=pr&el=h1) Report
> Merging [#17549](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/328c7e179b72e257e27adf92a06718fd5a40473f?src=pr&el=desc) will **decrease** coverage by `0.04%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/17549/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17549      +/-   ##
==========================================
- Coverage   91.25%    91.2%   -0.05%     
==========================================
  Files         163      163              
  Lines       49606    49606              
==========================================
- Hits        45266    45245      -21     
- Misses       4340     4361      +21
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.99% <ø> (-0.03%)` | :arrow_down: |
| #single | `40.19% <ø> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `63.23% <0%> (-1.82%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17549?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/17549?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/17549?src=pr&el=footer). Last update [328c7e1...e62515f](https://codecov.io/gh/pandas-dev/pandas/pull/17549?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).