Ipywidgets: alter slider defaults based on a scenario

Question

I'm using ipywidges to create a plot. I'd like to have a dropdown with options (e.g. Scenario A, Scenario B). Each scenario should change the slider position (a=0, b=1), and one should be able to modify the parameters freely afterwards. Any ideas?

Here is my toy example:

import ipywidgets as widgets

def line(a=0,b=1):
    #fig, ax = plt.subplots(figsize=(6, 4))
    x = np.arange(-10,10)
    y = a+xrange*b
    plt.xlim((-10,10))
    plt.ylim((-10,10))
    plt.plot(x, y)
    
widgets.interact(line, a=(-10,10,0.1), b=(-10,10,0.1))

I was playing with an additional wrapper functions but with no success. In reality of course, I would like to have a few more scenarios and a lot more parameters.

Answer 1

All right, I think I've found a very nice workaround:

def line(a=0,b=0):
    x = np.arange(-10,10)
    y = a+x*b
    plt.xlim((-10,10))
    plt.ylim((-10,10))
    plt.plot(x, y)

sliders = widgets.interact(a=(-10,10,0.1), b=(-10,10,0.1))

def test(chose_defaults):
    if chose_defaults=="a":
        @sliders
        def h(a=5,b=5):
            return(line(a,b))
    if chose_defaults=="b":
        @sliders
        def h(a=0,b=1):
            return(line(a,b))
widgets.interact(test, chose_defaults=["a","b"])

The above code basically nests two widgets. Firstly a separate widget for chosing a scenario is shown; action for the scenarios are the plots that differ only in the default setup.