pyplot_test.py

import matplotlib
matplotlib.use('Qt5Agg')
import matplotlib.pyplot as plt
import numpy as np
import time

plt.ion()
fig, ax = plt.subplots()
line, = ax.plot(np.random.randn(100))

tstart = time.time()
num_plots = 0
while time.time()-tstart < 3:
    line.set_ydata(np.random.randn(100))
    fig.canvas.draw()
    fig.canvas.flush_events()
    num_plots += 1
print(num_plots)
plt.show()