.sort(, descending=True) is not a stable sort

[davidwagner]

.sort('X') uses a stable sort: in the case of ties in column X, it preserves the existing order of the rows.

.sort('X', descending=True) is not a stable sort: in case of ties, it reverses the order of the rows. It appears to be behave as though we did .sort('X') and then reversed the order of the rows.

This is a bit surprising and counter-intuitive. Is it intentional? Is there an argument for why this behavior is better than the alternative of making descending=True also use a stable sort?

[papajohn]

Seems like a bug to me. (Probably one that I introduced.)

…

On Wed, Sep 23, 2020 at 6:22 PM davidwagner ***@***.***> wrote: .sort('X') uses a stable sort: in the case of ties in column X, it preserves the existing order of the rows. .sort('X', descending=True) is not a stable sort: in case of ties, it reverses the order of the rows. It appears to be behave as though we did .sort('X') and then reversed the order of the rows. This is a bit surprising and counter-intuitive. Is it intentional? Is there an argument for why this behavior is better than the alternative of making descending=True also use a stable sort? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#459>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACOFEJPVX4E6CMS5RWTA5LSHKNO5ANCNFSM4RXWHOXQ> .

[hmstepanek]

I can take a closer look at this.