知识问答

创建两个子图后如何共享它们的x轴？

内容 隐藏
问题：创建两个子图后如何共享它们的x轴？
回答 0

问题：创建两个子图后如何共享它们的x轴？

我正在尝试共享两个子图轴，但是在创建图形之后，我需要共享x轴。因此，例如，我创建了这个图：

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()

除了注释，我将插入一些代码以共享两个x轴。我没有找到任何线索我可以做到这一点。有一些属性 _shared_x_axes，_shared_x_axes当我检查图轴（fig.get_axes()）时，我不知道如何链接它们。

点击查看英文原文

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 and _shared_x_axes when i check to figure axis (fig.get_axes()) but I don’t know how to link them.

回答 0

共享轴的常用方法是在创建时创建共享属性。要么

fig=plt.figure()
ax1 = plt.subplot(211)
ax2 = plt.subplot(212, sharex = ax1)

要么 

fig, (ax1, ax2) = plt.subplots(nrows=2, sharex=True)

因此，无需在创建轴之后共享轴。

但是，如果出于任何原因，您需要在创建轴后共享轴（实际上，使用另一个库可以创建一些子图，例如here，或者共享插入轴可能是一个原因），仍然有解决方案：

使用 

ax1.get_shared_x_axes().join(ax1, ax2)

在两个轴之间创建链接，ax1并且ax2。与创建时的共享相比，您必须为其中一个轴手动设置xticklabel（以防万一）。

一个完整的例子：

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()
点击查看英文原文

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)

or 

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, or sharing an inset axes might be a reason), there would still be a solution:

Using 

ax1.get_shared_x_axes().join(ax1, ax2)

creates a link between the two axes, ax1 and 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()