Plotting in Jupyter notebooks¶

how to plot results in real time

In [2]:

import numpy as np
import matplotlib.pyplot as plt
from IPython.display import display, clear_output

method 1: clear axes before plotting

In [3]:

fig = plt.figure()
ax = fig.add_subplot(1, 1, 1) 

for i in range(20):
    x = np.arange(0, i, 0.1);
    y = np.sin(x)
    
    ax.set_xlim(0, i)
    
    ax.cla()
    ax.plot(x, y)
    display(fig)
    
    clear_output(wait = True)
    plt.pause(0.5)

method 2: set fixed x range and don't clear axes every step

In [4]:

fig = plt.figure()
ax = fig.add_subplot(1, 1, 1) 

for i in range(21):
    ax.set_xlim(0, 20)
    ax.set_ylim(-1.2, 1.2)
    
    ax.plot(i, np.sin(i),marker='x')
    display(fig)
    
    clear_output(wait = True)
    plt.pause(0.5)

clear_output(wait=True) will erase the current contents when the next content is displayed, so don't print anything after plotting!

In [6]:

fig = plt.figure()
ax = fig.add_subplot(1, 1, 1) 

for i in range(10):
    x = np.arange(0, i, 0.1);
    y = np.sin(x)
    
    ax.set_xlim(0, i)
    
    ax.cla()
    ax.plot(x, y)
    display(fig)
    
    clear_output(wait = True)
    plt.pause(0.5)
print("This message will erase the figure, be careful")

This message will erase the figure, be careful