Matplotlib animate fill_between shape

Question

I am trying to animate a fill_between shape inside matplotlib and I don\'t know how to update the data of the PolyCollection. Take this simple example: I have two lines and

Answer 1

Ok, as someone pointed out, we are dealing with a collection here, so we will have to delete and redraw. So somewhere in the update_data function, delete all collections associated with it:

axes_dummy.collections.clear()

and draw the new "fill_between" PolyCollection:

axes_dummy.fill_between(x, y-sigma, y+sigma, facecolor='yellow', alpha=0.5)

A similar trick is required to overlay an unfilled contour plot on top of a filled one, since an unfilled contour plot is a Collection as well (of lines I suppose?).