DOC: Updating str_slice docstring
Added Examples to docstring.
Added documentation to each part of docstring
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22569?src=pr&el=h1) Report
> Merging [#22569](https://codecov.io/gh/pandas-dev/pandas/pull/22569?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/6247da0db4835ff723126640145b4fad3ce17343?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/22569/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22569?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #22569      +/-   ##
==========================================
- Coverage   92.19%   92.18%   -0.01%     
==========================================
  Files         169      169              
  Lines       50833    50823      -10     
==========================================
- Hits        46863    46853      -10     
  Misses       3970     3970
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.6% <ø> (ø)` | :arrow_up: |
| #single | `42.36% <ø> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/22569?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/strings.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc3RyaW5ncy5weQ==) | `98.63% <ø> (ø)` | :arrow_up: |
| [pandas/core/groupby/grouper.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS9ncm91cGVyLnB5) | `97.42% <0%> (-0.74%)` | :arrow_down: |
| [pandas/core/internals/blocks.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL2Jsb2Nrcy5weQ==) | `93.48% <0%> (-0.37%)` | :arrow_down: |
| [pandas/core/dtypes/dtypes.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2R0eXBlcy5weQ==) | `95.85% <0%> (-0.26%)` | :arrow_down: |
| [pandas/core/arrays/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2NhdGVnb3JpY2FsLnB5) | `95.62% <0%> (-0.13%)` | :arrow_down: |
| [pandas/io/pytables.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3B5dGFibGVzLnB5) | `92.44% <0%> (-0.05%)` | :arrow_down: |
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `96.65% <0%> (-0.02%)` | :arrow_down: |
| [pandas/core/indexes/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZWxpa2UucHk=) | `98.11% <0%> (ø)` | :arrow_up: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.2% <0%> (ø)` | :arrow_up: |
| [pandas/core/indexes/multi.py](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9tdWx0aS5weQ==) | `95.45% <0%> (ø)` | :arrow_up: |
| ... and [13 more](https://codecov.io/gh/pandas-dev/pandas/pull/22569/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22569?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/22569?src=pr&el=footer). Last update [6247da0...d49a2e7](https://codecov.io/gh/pandas-dev/pandas/pull/22569?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @JesperDramsch do you have time to update this PR based on the comments? > @JesperDramsch do you have time to update this PR based on the comments?

Totally missed this one. I'll get to it asap Hello @JesperDramsch! Thanks for updating the PR.

 - There are no PEP8 issues in the file [`pandas/core/strings.py`](https://github.com/JesperDramsch/pandas/blob/d49a2e7dc2cd257a3e16055d313c60dff61b2fd9/pandas/core/strings.py) !



##### Comment last updated on October 03, 2018 at 21:27 Hours UTC Here we go. Ran validation and updated everything according to the comments and linter. Thank you for the comments @datapythonista and thanks for the patience @jorisvandenbossche.

 @JesperDramsch can you rebase, so the CI runs again, and we can merge it? > @JesperDramsch can you rebase, so the CI runs again, and we can merge it?

I'm not really sure what that means. How do I rebase?
Do you have a link? Sorry, we use rebase as short for updating your PR with the latest master.

Just run in your branch: `git fetch upstream && git merge upstream/master && git push`.

This is usually required when the branch of the PR has conflicts with master. In this case github would manage the merge itself, as there are no conflicts. But as the checks of the CI failed (for reasons unrelated to your PR), we just want them to run again. And as there are many systems, and I don't thing I even have permissions to all them, the easiest is that you update your branch, and then all them are automatically rerun.

With some luck we'll make things easier soon. :) Alright. I can get to that tomorrow easily. @JesperDramsch seems like there is a formatting issue `pandas/core/strings.py:1497:1: W293 blank line contains whitespace`, that's why travis is failing.

Can you fix it please. Happy to merge it afterwards. Aw Yiss. Thanks for another great docstring @JesperDramsch 