secondary Y axis position matplotlib

Question

I need to change the secondary Y axis position on a matplotlib plot.

It's like a subplot inside the same plot.

In the image below, my secondary Y axis starts at the same position as first y axis. I need that the secondary Y axis starts about at the "18" position of the first Y axis, with a smaller scale (red line).

Answer 1

If I understand the question, you want a twinx axis, as @kikocorreoso says, but you also want to compress it, so it only takes up the upper portion of the y axis.

You can do this by just setting the ylim larger than you need it, and explicitly setting the yticks. Here's an example with some random data

import matplotlib.pyplot as plt
import numpy as np

data = [np.random.normal(np.random.randint(0,5),4,25) for _ in range(25)] # some random data

fig=plt.figure()
ax1=fig.add_subplot(111)
ax2=ax1.twinx()

ax1.set_ylim(-5,25)
ax2.set_ylim(0,14)
ax2.set_yticks([10,12,14]) # ticks below 10 don't show up

ax1.boxplot(data)
ax2.plot(np.linspace(0,26,50),12.+2.*np.sin(np.linspace(0,2.*np.pi,50))) # just a random line

plt.show()