Implement/dispatch unary operations for ExtensionArrays

[jorisvandenbossche]

xref https://github.com/pandas-dev/pandas/pull/22325/files#r220580694

unary ops are not implemented by EAs and also not dispatched to EAs:

In [161]: s = pd.Series([1, 2, 3], dtype='Int64')

In [162]: -s
Out[162]: 
0    -1
1    -2
2    -3
dtype: object

[jorisvandenbossche]

Moved to 0.25.0 milestone

[TomAugspurger]

Probably not a blocker for 1.0 right?

[mroeschke]

Looks like this got implemented at some point. Probably good to see if there are tests

In [11]: s = pd.Series([1, 2, 3], dtype='Int64')

In [12]: -s
Out[12]:
0    -1
1    -2
2    -3
dtype: Int64