idxmax with multiple dimensions

[max-sixty]

Is your feature request related to a problem?

(I thought we had an issue for this, but can't find it after five minutes of looking, so either we don't or I've done a very bad job searching...)

idxmax (+ idxmin) doesn't accept multiple dimensions, but argmax does.

Describe the solution you'd like

Could we implement idxmax as a wrapper of argmax?

Describe alternatives you've considered

No response

Additional context

Possibly it's just me, but fwiw I find the idxmax & argmax terms very confusing, constantly have to look up which is which... I guess it doesn't help that the description of argmax is "Index or indices of the maximum"...! But I'm not sure there's a good way of making these much better — maybe in a vacuum we could have started with names like label_max & index_max, or argmax & iargmax, but tough to change now.

[dcherian]

arg* is standard for array apis. I think we copied the idx* naming from pandas.

Could we implement idxmax as a wrapper of argmax?

👍 At present, it seems like it calls the arg* duck array op.