Save matplolib figure in Pickle and open it in Jupyter Notebook

Community
1

Hello,

Is it possible to dump the matplotlib plot in Pickle using the default figure manager and load it in Jupyter notebook.
Basically I tried now to save a plot by running a .py file

`
import numpy as np
import matplotlib.pyplot as plt
import pickle

x = np.linspace(-np.pi, np.pi)
y = np.cos(x)
fig, ax = plt.subplots(1, 1)
ax.plot(x, y, label=‘cos(x)’)
ax.set_xlabel(‘Time (s)’)

pickle.dump((fig, ax), open(‘myplot.pickle’, ‘wb’))
`

and then load the produced pickle in a Jupyter Notebook:

`
import matplotlib.pyplot as plt
import pickle

fig, ax = pickle.load(open(‘myplot.pickle’, ‘rb’))
ax.set_ylabel(‘Voltage (mV)’)
ax.minorticks_on()
ax.legend()
`

I always get the following message.

AttributeError: 'NoneType' object has no attribute 'new_figure_manager_given_figure'

2

That code works for me. I suspect your output and input versions of Matplotlib are different - the pickle objects are not portable across version changes of Matplotlib.

3

Hi,

Sorry about the delay. I was in vacation. I have the same matplotlib version (3.5.2).
So you did like me?

  1. Create the file by running a python script (.py) that uses the default backend (I am on windows) and save the figure as pickle
  2. Try to load the same pickle in Jupyter notebook (ipynb)

I had the feeling it came from the fact they have different backends but maybe I am wrong…

4

Thats possible. I didn’t test that.

I’m personally pretty against pickling figures. Usually it’s just as well to save the data and re-plot. However I can see the use if you have made a bunch of manual changes.