API: add top-level functions as method (original) (raw)

xref #12578

so its pretty easy to add (and eventually deprecate) certain top-level functions that could/should be methods. Promotes a cleaner syntax and method chaining.

In 0.18.1 would propose adding these, deprecating in 0.19.0.

This would eliminate the ability to use directly with np.ndarrays, but I view this is as a positive (note we effectively did this for the .rolling/expanding/ewm with np.ndarrays as well, though deprecated for a while).