将python matplotlib图形另存为pickle

Question

I want to save matplotlib figures as pickle, to enable my team to easily load them and investigate anomalous events. Using a simple image format loses the ability to zoom-in and investigate the figure. So I tried to pickle my figure:

fig, axarr = plt.subplots(2, sharex='all') # creating the figure
... # plotting things
...
pickle.dump(fig, open('myfigfile.p'), 'wb'))

Then I load it. Looks good. At first.

fig = pickle.load(open('myfigfile.p', 'rb'))
plt.show()

But then I see that sharex doesn't work. When I zoom-in on one subplot, the other remains static. On the original plot this works great, and zooming-in zooms on both x-axis, but after I pickle-load the figure, this doesn't work anymore. How can I save the plot so that it continues to share-x after loading? Or, how can I reinstate share-x after loading the figure from the pickle?

Thanks!

Answer 1

In the current development version of matplotlib this should work due to the fix provided .

With the current released version of matplotlib, would need to reestablish the sharing eg like

import matplotlib.pyplot as plt
import pickle

fig, axes = plt.subplots(ncols=3, sharey="row")
axes[0].plot([0,1],[0,1])
axes[1].plot([0,1],[1,2])
axes[2].plot([0,1],[2,3])

pickle.dump(fig, file('fig1.pkl', 'wb'))  

plt.close("all")

fig2 = pickle.load(file('fig1.pkl','rb'))
ax_master = fig2.axes[0]
for ax in fig2.axes:
    if ax is not ax_master:
        ax_master.get_shared_y_axes().join(ax_master, ax)

plt.show()

This has the drawback that you need to know which axes to share. In the case of all axes being shared this is of course easy, as shown above.