[FIXED] Telling IPython interact widget to ignore self argument in OOP

Issue

I'm trying to use the IPython interact widget for a particular method in one of my classes. I would like it to ignore the self & colour arguments, and only adjust the i argument, but it insists that self is a bonafide argument too.

A similar question was asked here, but neither method (using fixed on self or pre-loading self into the method with partial) is appropriate in this case.

from ipywidgets.widgets import interact,fixed
import matplotlib.pyplot as plt

class Profile():
'''self.stages is a list of lists'''
    @interact(i=(0,5,1),colour=fixed(DEFAULT_COLOR))
    def plot_stages(self, i, colour):
        plt.plot(self.stages[i], color=colour)

This returns an error: ValueError: cannot find widget or abbreviation for argument: 'self'

So how does one tell interact to ignore the self argument?

Solution

Define an “outer” function that takes the self and the constant arguments. Inside that define an “inner” function that takes only the interactive arguments as parameters and can access self and the constant arguments from the outer scope.

from ipywidgets.widgets import interact
import matplotlib.pyplot as plt

DEFAULT_COLOR = 'r'
class Profile():
    '''self.stages is a list of lists'''
    stages = [[-1, 1, -1], [1, 2, 4], [1, 10, 100], [0, 1, 0], [1, 1, 1]]

    def plot_stages(self, colour):
        def _plot_stages(i):
            plt.plot(self.stages[i], color=colour)

        interact(_plot_stages, i=(0, 4, 1))

p = Profile()
p.plot_stages(DEFAULT_COLOR)

Answered By - hfs