feat(python): deprecate boolean mask for Series indexing

[matteosantama]

For consistency with #4342, I think we should soon drop support for Series.__getitem__ with a boolean mask. Instead, we should encourage users to use Series.filter.

If this looks ok, I will add the breaking change to the PR I am working on for #4924

(As a little bonus I've added overloaded Series.__getitem__. This change is a no-brainer.)

[ritchie46]

Good one. Thanks

[slonik-az]

we should encourage users to use Series.filter.

I am curious what would be a recommended ergonomic way of conditional assignment in place if ser[ser < 0] = 0 is not possible anymore? when/then/otherwise does not modify in place.

[ritchie46]

when/then/otherwise does not modify in place.

It can be in place (from a memory perspective), if the memory is not shared.
ser[ser < 0] = 0 on the other hand can also be a full data copy (from a memory perspective).

I think we should keep allowing the __setitem__. But it will remain an anti-pattern. As it may still do a full data copy, and if you do those repeatedly it will be very expensive/single threaded , etc.