BUG-22984 Fix truncation of DataFrame representations
- [X] closes #22984 
- [X] tests added / passed
- [X] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [X] whatsnew entry

When printing a DataFrame to terminal, an extra column's worth of space is added to the calculated width of the DataFrame. This is presumably to help edge cases, but the calculated difference between the DataFrame width and the terminal window width is incremented by 1 a few lines later, seemingly to fix the same problem. Do any more experienced developers know of a reason to pad the DataFrame width even more?
Hello @JustinZhengBC! Thanks for updating the PR.

 - There are no PEP8 issues in the file [`pandas/io/formats/format.py`](https://github.com/JustinZhengBC/pandas/blob/6b54cf8bf0b4531d2fd8c38211822a89319b6b73/pandas/io/formats/format.py) !

 - There are no PEP8 issues in the file [`pandas/tests/io/formats/test_format.py`](https://github.com/JustinZhengBC/pandas/blob/6b54cf8bf0b4531d2fd8c38211822a89319b6b73/pandas/tests/io/formats/test_format.py) !



##### Comment last updated on October 07, 2018 at 01:59 Hours UTC # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=h1) Report
> Merging [#22987](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/fb4405d5ebc132f50103b500592109988ad6a0c5?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/22987/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #22987      +/-   ##
==========================================
- Coverage   92.24%   92.24%   -0.01%     
==========================================
  Files         161      161              
  Lines       51340    51315      -25     
==========================================
- Hits        47361    47336      -25     
  Misses       3979     3979
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.63% <ø> (-0.01%)` | :arrow_down: |
| #single | `42.31% <ø> (-0.04%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/formats/format.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvZm9ybWF0LnB5) | `97.88% <ø> (-0.01%)` | :arrow_down: |
| [pandas/core/arrays/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3RpbWVkZWx0YXMucHk=) | `95.08% <0%> (-0.56%)` | :arrow_down: |
| [pandas/core/dtypes/concat.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2NvbmNhdC5weQ==) | `96.26% <0%> (-0.41%)` | :arrow_down: |
| [pandas/core/arrays/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lbGlrZS5weQ==) | `95.92% <0%> (-0.22%)` | :arrow_down: |
| [pandas/core/arrays/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lcy5weQ==) | `98.44% <0%> (-0.04%)` | :arrow_down: |
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `96.12% <0%> (ø)` | :arrow_up: |
| [pandas/core/arrays/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3BlcmlvZC5weQ==) | `98.49% <0%> (+0.04%)` | :arrow_up: |
| [pandas/tseries/offsets.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvb2Zmc2V0cy5weQ==) | `97.07% <0%> (+0.08%)` | :arrow_up: |
| [pandas/core/indexes/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZWxpa2UucHk=) | `98.01% <0%> (+0.27%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22987?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/22987?src=pr&el=footer). Last update [fb4405d...139235a](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 cc @jorisvandenbossche  lgtm. @TomAugspurger a glance if you can. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=h1) Report
> Merging [#22987](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/e413c491e090274aad78489cc17a2e29cbd8e269?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/22987/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #22987      +/-   ##
==========================================
- Coverage   92.24%   92.24%   -0.01%     
==========================================
  Files         161      161              
  Lines       51339    51336       -3     
==========================================
- Hits        47360    47357       -3     
  Misses       3979     3979
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.64% <ø> (-0.01%)` | :arrow_down: |
| #single | `42.34% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/formats/format.py](https://codecov.io/gh/pandas-dev/pandas/pull/22987/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvZm9ybWF0LnB5) | `97.88% <ø> (-0.01%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22987?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/22987?src=pr&el=footer). Last update [e413c49...82fa50c](https://codecov.io/gh/pandas-dev/pandas/pull/22987?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @JustinZhengBC need to merge master Another hypothesis failure on azure. OK to merge @jreback? I can investigate the failing test separately. yep Merged master to fix the confict. May as well let the CI run.

ping on green. @TomAugspurger green. Also thanks for fixing the merge issue I caused it my merging my own PR, so it's the least I could do :)

Thanks!