restrict columns to read for pandas.read_parquet
State: closed

- [ x ] closes #18154
- [ x ] tests added / passed
- [ x ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Labels:
name: Enhancement
name: IO Parquet
description: parquet, feather

Comments:
Will need a `whatsnew` note in `0.22.0`
Hello @hoffmann! Thanks for updating the PR.





Cheers ! There are no PEP8 issues in this Pull Request. :beers: 

##### Comment last updated on November 08, 2017 at 13:04 Hours UTC
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=h1) Report
> Merging [#18155](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/488db6f9a0f19e1d18559e6c2056e9545fe14704?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `83.33%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/18155/graphs/tree.svg?height=150&src=pr&token=eZ4WkYLtcO&width=650)](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #18155      +/-   ##
==========================================
+ Coverage   91.41%   91.41%   +<.01%     
==========================================
  Files         163      163              
  Lines       50132    50132              
==========================================
+ Hits        45827    45830       +3     
+ Misses       4305     4302       -3
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.23% <83.33%> (+0.02%)` | :arrow_up: |
| #single | `40.33% <50%> (-0.06%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/parquet.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2lvL3BhcnF1ZXQucHk=) | `65.38% <83.33%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.8% <0%> (-0.1%)` | :arrow_down: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `65.2% <0%> (+1.81%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18155?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/18155?src=pr&el=footer). Last update [488db6f...21c5f5e](https://codecov.io/gh/pandas-dev/pandas/pull/18155?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/18155?src=pr&el=h1) Report
> Merging [#18155](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/488db6f9a0f19e1d18559e6c2056e9545fe14704?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `83.33%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/18155/graphs/tree.svg?height=150&width=650&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #18155      +/-   ##
==========================================
- Coverage   91.41%    91.4%   -0.01%     
==========================================
  Files         163      163              
  Lines       50132    50068      -64     
==========================================
- Hits        45827    45767      -60     
+ Misses       4305     4301       -4
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.21% <83.33%> (+0.01%)` | :arrow_up: |
| #single | `40.33% <50%> (-0.06%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/parquet.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2lvL3BhcnF1ZXQucHk=) | `65.38% <83.33%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.8% <0%> (-0.1%)` | :arrow_down: |
| [pandas/tseries/offsets.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvb2Zmc2V0cy5weQ==) | `97.11% <0%> (-0.05%)` | :arrow_down: |
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `95.48% <0%> (-0.04%)` | :arrow_down: |
| [pandas/core/indexes/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy90aW1lZGVsdGFzLnB5) | `91.17% <0%> (-0.02%)` | :arrow_down: |
| [pandas/core/nanops.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvbmFub3BzLnB5) | `96.67% <0%> (ø)` | :arrow_up: |
| [pandas/core/indexes/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZWxpa2UucHk=) | `97.11% <0%> (ø)` | :arrow_up: |
| [pandas/core/indexes/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9wZXJpb2QucHk=) | `92.89% <0%> (+0.01%)` | :arrow_up: |
| [pandas/core/tools/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvdG9vbHMvdGltZWRlbHRhcy5weQ==) | `98.41% <0%> (+0.02%)` | :arrow_up: |
| ... and [1 more](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18155?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/18155?src=pr&el=footer). Last update [488db6f...4b22c88](https://codecov.io/gh/pandas-dev/pandas/pull/18155?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).

you have a linting issue
ping on green
@jreback green. 

If it's ok I'd like to do the change to accept **kwargs in the read() function in a different pull request because it will require to rewrite https://github.com/pandas-dev/pandas/blob/master/pandas/tests/io/test_parquet.py#L191 to be able to handle **kwargs for to_parquet and read_parquet at the same time. 
> If it's ok I'd like to do the change to accept **kwargs in the read() function in a different pull request because it will require to rewrite https://github.com/pandas-dev/pandas/blob/master/pandas/tests/io/test_parquet.py#L191 to be able to handle **kwargs for to_parquet and read_parquet at the same time.

yep ok by me
thanks!