Collect Index methods by purpose: rendering, constructors, setops...
Zero changes to the contents of _any_ methods, just collecting them in reasonably-scoped sections.
Hello @jbrockmendel! Thanks for submitting the PR.

 - There are no PEP8 issues in the file [`pandas/core/indexes/base.py`](https://github.com/jbrockmendel/pandas/blob/32d389e034163188d51fa973d8bff46cfc014cbc/pandas/core/indexes/base.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/category.py`](https://github.com/jbrockmendel/pandas/blob/32d389e034163188d51fa973d8bff46cfc014cbc/pandas/core/indexes/category.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/datetimelike.py`](https://github.com/jbrockmendel/pandas/blob/32d389e034163188d51fa973d8bff46cfc014cbc/pandas/core/indexes/datetimelike.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/datetimes.py`](https://github.com/jbrockmendel/pandas/blob/32d389e034163188d51fa973d8bff46cfc014cbc/pandas/core/indexes/datetimes.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/interval.py`](https://github.com/jbrockmendel/pandas/blob/32d389e034163188d51fa973d8bff46cfc014cbc/pandas/core/indexes/interval.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/multi.py`](https://github.com/jbrockmendel/pandas/blob/32d389e034163188d51fa973d8bff46cfc014cbc/pandas/core/indexes/multi.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/period.py`](https://github.com/jbrockmendel/pandas/blob/32d389e034163188d51fa973d8bff46cfc014cbc/pandas/core/indexes/period.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/range.py`](https://github.com/jbrockmendel/pandas/blob/32d389e034163188d51fa973d8bff46cfc014cbc/pandas/core/indexes/range.py) !

 - There are no PEP8 issues in the file [`pandas/core/indexes/timedeltas.py`](https://github.com/jbrockmendel/pandas/blob/32d389e034163188d51fa973d8bff46cfc014cbc/pandas/core/indexes/timedeltas.py) !

 travis failure appears unrelated # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23961?src=pr&el=h1) Report
> Merging [#23961](https://codecov.io/gh/pandas-dev/pandas/pull/23961?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/6b4b9560eba3d18e3fdcf2e5e8e9ac64fbaa5ecc?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/23961/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/23961?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #23961      +/-   ##
==========================================
+ Coverage   92.31%   92.31%   +<.01%     
==========================================
  Files         161      161              
  Lines       51471    51473       +2     
==========================================
+ Hits        47515    47517       +2     
  Misses       3956     3956
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.7% <100%> (ø)` | :arrow_up: |
| #single | `42.43% <49.76%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/23961?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/category.py](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9jYXRlZ29yeS5weQ==) | `97.87% <ø> (ø)` | :arrow_up: |
| [pandas/core/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9iYXNlLnB5) | `96.48% <ø> (ø)` | :arrow_up: |
| [pandas/core/indexes/range.py](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9yYW5nZS5weQ==) | `97.32% <ø> (ø)` | :arrow_up: |
| [pandas/core/indexes/multi.py](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9tdWx0aS5weQ==) | `95.49% <100%> (ø)` | :arrow_up: |
| [pandas/core/indexes/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9wZXJpb2QucHk=) | `93.07% <100%> (ø)` | :arrow_up: |
| [pandas/core/indexes/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZWxpa2UucHk=) | `97.74% <100%> (ø)` | :arrow_up: |
| [pandas/core/indexes/interval.py](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9pbnRlcnZhbC5weQ==) | `94.69% <100%> (ø)` | :arrow_up: |
| [pandas/core/indexes/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy90aW1lZGVsdGFzLnB5) | `89.18% <100%> (ø)` | :arrow_up: |
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `96.47% <100%> (ø)` | :arrow_up: |
| ... and [1 more](https://codecov.io/gh/pandas-dev/pandas/pull/23961/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23961?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/23961?src=pr&el=footer). Last update [6b4b956...a70b319](https://codecov.io/gh/pandas-dev/pandas/pull/23961?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 collected uncategorized methods in one block just above generated-methods.  implemented the subset of suggestions that didn't need clarification.

This is liable to become a rebasing nightmare if left open.  I think should be multi-pass process. thanks. if any comments you didn't address here, pls do in a followup.