BUG: Accept Generic Array-Like for .where
Setup:
~~~python
>>> s = Series([1, 2, 3])
>>> cond = [False, True, True]
~~~
Before:
~~~python
>>> s.where(cond)
...
ValueError: where requires an ndarray like object for its condition
~~~
After:
~~~python
>>> s.where(cond)
0    NaN
1    2.0
2    3.0
dtype: float64
~~~

Note that `Index` objects can accept array-like objects as conditionals, and I wrote tests to confirm.
don't suppose there is an issue about this outstanding? > don't suppose there is an issue about this outstanding?

No, there is not.  I just stumbled across this while grappling with the `NaN` in integer `Index`. @jreback : The Appveyor build is broken for everybody due to `conda` conflicts. > The Appveyor build is broken for everybody due to conda conflicts.

hmm, that's not friendly I think the miniconda installer changed to 3.6. > I think the miniconda installer changed to 3.6.

Yikes...though the installer website page doesn't seem to reflect that if that's true... neah its not that. I had fixed the conda installer a while back at 4.2.15. So was installing the latest miniconda, but an incompat version of conda :<

switching to latest fixes. pushing soon. ok rebase and windows should be good. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15414?src=pr&el=h1) Report
> Merging [#15414](https://codecov.io/gh/pandas-dev/pandas/pull/15414?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/81c57e20da278494dfebc2f1043f5ff361a234f3?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.


```diff
@@            Coverage Diff             @@
##           master   #15414      +/-   ##
==========================================
+ Coverage   90.36%   90.36%   +<.01%     
==========================================
  Files         136      136              
  Lines       49532    49540       +8     
==========================================
+ Hits        44760    44768       +8     
  Misses       4772     4772
```


| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/15414?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/compare/81c57e20da278494dfebc2f1043f5ff361a234f3...5037932f78ebdee297c26eaf65585e7290b4ef32?src=pr&el=tree#diff-cGFuZGFzL2luZGV4ZXMvYmFzZS5weQ==) | `96.22% <ø> (ø)` | :white_check_mark: |
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/compare/81c57e20da278494dfebc2f1043f5ff361a234f3...5037932f78ebdee297c26eaf65585e7290b4ef32?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `96.31% <100%> (+0.01%)` | :white_check_mark: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15414?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/15414?src=pr&el=footer). Last update [81c57e2...5037932](https://codecov.io/gh/pandas-dev/pandas/compare/81c57e20da278494dfebc2f1043f5ff361a234f3...5037932f78ebdee297c26eaf65585e7290b4ef32?el=footer&src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments). thanks. I looked at the previous code and realize that ``inplace`` was being used similarly to how you are using it. I think the alignment in ``.where`` is a mistake, but it probably is never used. We don't do alignment on boolean things anywhere else. So should remove this