Answer: Animating a Matplotlib chart

matplotlib_animation.py

import matplotlib.pyplot as plt
import numpy as np
import streamlit as st
import time

fig, ax = plt.subplots()

max_x = 5
max_rand = 10

x = np.arange(0, max_x)
ax.set_ylim(0, max_rand)
line, = ax.plot(x, np.random.randint(0, max_rand, max_x))
the_plot = st.pyplot(plt)

def init():  # give a clean slate to start
    line.set_ydata([np.nan] * len(x))

def animate(i):  # update the y values (every 1000ms)
    line.set_ydata(np.random.randint(0, max_rand, max_x))
    the_plot.pyplot(plt)

init()
for i in range(100):
    animate(i)
    time.sleep(0.1)

Created in response to this question.

With newer streamlit versions starting from 0.52.2 and upwards, you need to provide the clear_figure=False flag to both .pyplot(plt) calls. More on this in this issue.