I’m trying to share two subplots axis, but I need to share x axis after the figure was created.
So, for instance, I create this figure:
import numpy as np import matplotlib.pyplot as plt t= np.arange(1000)/100. x = np.sin(2*np.pi*10*t) y = np.cos(2*np.pi*10*t) fig=plt.figure() ax1 = plt.subplot(211) plt.plot(t,x) ax2 = plt.subplot(212) plt.plot(t,y) # some code to share both x axis plt.show()
Instead of the comment I would insert some code to share both x axis.
I didn’t find any clue how i can do that. There are some attributes
_shared_x_axes when i check to figure axis (
fig.get_axes()) but I don’t know how to link them.
The usual way to share axes is to create the shared properties at creation. Either
fig=plt.figure() ax1 = plt.subplot(211) ax2 = plt.subplot(212, sharex = ax1)
fig, (ax1, ax2) = plt.subplots(nrows=2, sharex=True)
Sharing the axes after they have been created should therefore not be necessary.
However if for any reason, you need to share axes after they have been created (actually, using a different library which creates some subplots, like here might be a reason), there would still be a solution:
creates a link between the two axes,
ax2. In contrast to the sharing at creation time, you will have to set the xticklabels off manually for one of the axes (in case that is wanted).
A complete example:
import numpy as np import matplotlib.pyplot as plt t= np.arange(1000)/100. x = np.sin(2*np.pi*10*t) y = np.cos(2*np.pi*10*t) fig=plt.figure() ax1 = plt.subplot(211) ax2 = plt.subplot(212) ax1.plot(t,x) ax2.plot(t,y) ax1.get_shared_x_axes().join(ax1, ax2) ax1.set_xticklabels() # ax2.autoscale() ## call autoscale if needed plt.show()
Just to add to ImportanceOfBeingErnest’s answer above:
If you have an entire
list of axes objects, you can pass them all at once and have their axes shared by unpacking the list like so:
ax_list = [ax1, ax2, ... axn] #< your axes objects ax_list.get_shared_x_axes().join(*ax_list)
The above will link all of them together. Of course, you can get creative and sub-set your
list to link only some of them.
In order to have all
axes linked together, you do have to include the first element of the
axes_list in the call, despite the fact that you are invoking
.get_shared_x_axes() on the first element to start with!
So doing this, which would certainly appear logical:
… will result in linking all
axes objects together except the first one, which will remain entirely independent from the others.