I'm learning about using the slider and button widgets and am studying the example given in the link.
Slider Demo
Slider Demo
import numpy as np import matplotlib.pyplot as plt from matplotlib.widgets import Slider, Button, RadioButtons fig, ax = plt.subplots() plt.subplots_adjust(left=0.25, bottom=0.25) t = np.arange(0.0, 1.0, 0.001) a0 = 5 f0 = 3 delta_f = 5.0 s = a0 * np.sin(2 * np.pi * f0 * t) l, = plt.plot(t, s, lw=2) plt.axis([0, 1, -10, 10]) axcolor = 'lightgoldenrodyellow' axfreq = plt.axes([0.25, 0.1, 0.65, 0.03], facecolor=axcolor) axamp = plt.axes([0.25, 0.15, 0.65, 0.03], facecolor=axcolor) sfreq = Slider(axfreq, 'Freq', 0.1, 30.0, valinit=f0, valstep=delta_f) samp = Slider(axamp, 'Amp', 0.1, 10.0, valinit=a0) def update(val): amp = samp.val freq = sfreq.val l.set_ydata(amp*np.sin(2*np.pi*freq*t)) fig.canvas.draw_idle() sfreq.on_changed(update) samp.on_changed(update) resetax = plt.axes([0.8, 0.025, 0.1, 0.04]) button = Button(resetax, 'Reset', color=axcolor, hovercolor='0.975') def reset(event): sfreq.reset() samp.reset() button.on_clicked(reset) rax = plt.axes([0.025, 0.5, 0.15, 0.15], facecolor=axcolor) radio = RadioButtons(rax, ('red', 'blue', 'green'), active=0) def colorfunc(label): l.set_color(label) fig.canvas.draw_idle() radio.on_clicked(colorfunc) plt.show()I don't understand the parameters of the two first functions in the example nor the fact that they don't have any return statements. It seems like the parameters aren't used in the function, yet they're needed. I'd appreciate a clarification on what is going on. Thanks!