How to animate the title using FuncAnimation in Python?

Question

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation

fig = plt.figure()
axis = plt.axes(xlim=(-4, 4), ylim=(-3, 3))
line, = axis.plot([], [],'r+', lw=2)
plt.title('omega = {}')

def init():
    line.set_data([], [])
    return line,

def animate(i):
    y = omega[i]*np.sin(x)
    line.set_data(x, y)
    return line,

x = np.arange(-4, 4+0.1, 0.1)
domega = 0.25
omega = np.arange(-3, 3+domega, domega)

anim = FuncAnimation(fig, animate, init_func=init, frames=omega.size, interval=120, blit=False)

plt.show()

I want to plot y=omega*sin(x), which omega is start from -3 to 3 with step size 0.25, and x start from -4 to 4 with step size 0.1. I can animate it with above code.

Now, I want add the animated title "omega = ..." (the value of omega is suitable with moving curve). I don't know how to do it. I just can add plt.title('omega = {}'). So, how to animate the title in FuncAnimation? Any help be very appreciated.

Answer 1

Inside animate() use plt.title() or axis.title.set_text() with new text.

And you can use f-string to format it.

def animate(i):

    # use 5 places (also count `-` and `.`), and always two digits after dot
    plt.title(  f'omega = {omega[i]:5.2f}' )
    #axis.title.set_text(f'omega = {omega[i]:5.2f}')

    y = omega[i]*np.sin(x)
    line.set_data(x, y)
    return line,