Dynamic plot works in IDLE, but not jupyter notebook

问题

The code below works fine when running through idle (Python 3.6 idle)

import matplotlib.pyplot as plt
import time
import random
#%matplotlib inline

ysample = random.sample(range(-50, 50), 100)

xdata = []
ydata = []

plt.show()

axes = plt.gca()
axes.set_xlim(0, 100)
axes.set_ylim(-50, +50)
line, = axes.plot(xdata, ydata, 'r-')

for i in range(100):
    xdata.append(i)
    ydata.append(ysample[i])
    line.set_xdata(xdata)
    line.set_ydata(ydata)
    plt.draw()
    plt.pause(1e-17)
    time.sleep(0.1)

# add this if you don't want the window to disappear at the end
plt.show()

When transferring this code to jupyter notebook, I'm adding the magic command

%matplotlib notebook which I'm told should be used for dynamic plots.

(I tried %matplotlib inline, but I end up with a static plot)

However, I'm ending up with this error

 NotImplementedError                       Traceback (most recent call last)
<ipython-input-7-2f88f762e22a> in <module>()
     22     line.set_ydata(ydata)
     23     plt.draw()
---> 24     plt.pause(1e-17)
     25     time.sleep(0.1)
     26 

 C:\Users\Moondra\AppData\Local\Programs\Python\Python36\lib\site-
   packages\matplotlib\pyplot.py in pause(interval)
    298                 canvas.draw()
    299             show(block=False)
--> 300             canvas.start_event_loop(interval)
    301             return
    302 

C:\Users\Moondra\AppData\Local\Programs\Python\Python36\lib\site-packages\matplotlib\backends\backend_nbagg.py in start_event_loop(self, timeout)
    192 
     193     def start_event_loop(self, timeout):
--> 194         FigureCanvasBase.start_event_loop_default(self, timeout)
    195 
    196     def stop_event_loop(self):

C:\Users\Moondra\AppData\Local\Programs\Python\Python36\lib\site-
packages\matplotlib\backend_bases.py in start_event_loop_default(self, timeout)
   2451         self._looping = True
   2452         while self._looping and counter * timestep < timeout:
-> 2453             self.flush_events()
   2454             time.sleep(timestep)
   2455             counter += 1

     C:\Users\Moondra\AppData\Local\Programs\Python\Python36\lib\site-
 packages\matplotlib\backend_bases.py in flush_events(self)
   2400         backends with GUIs.
   2401         """
-> 2402         raise NotImplementedError
   2403 
   2404     def start_event_loop(self, timeout):

NotImplementedError:`

回答1:

plt.draw() doesn't work with the %matplotlib notebook, it's meant to be used in interactive mode, just as you used it in IDLE.

To overcome this there is an animation submodule which can be used.

import matplotlib.pyplot as plt
import matplotlib.animation
import time
import random
%matplotlib notebook

ysample = random.sample(range(-50, 50), 100)

xdata = []
ydata = []

axes = plt.gca()
axes.set_xlim(0, 100)
axes.set_ylim(-50, +50)
line, = axes.plot(xdata, ydata, 'r-')

def update(i):
    xdata.append(i)
    ydata.append(ysample[i])
    line.set_xdata(xdata)
    line.set_ydata(ydata)

ani= matplotlib.animation.FuncAnimation(plt.gcf(), update, frames=100,
                                       interval=100, repeat=False)

plt.show()

For more examples refer to the matplotlib page.

来源：https://stackoverflow.com/questions/43663613/dynamic-plot-works-in-idle-but-not-jupyter-notebook

标签

matplotlib

jupyter-notebook

python-3.6