How to use twinx()

import modules

import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline
plt.style.use('bmh')

prepare dummy datas

X = np.linspace(1, 10, 100)

y1 = X * 2.0
y2 = -4.0 * X + 25.0 

prepare plotting twinx()

fig, ax = plt.subplots(1, 1)
ax2 = ax.twinx()

plot left bar

ax.plot(X, y1)
ax.set_ylim(0, 30)
ax.set_ylabel('y1 for left_bar [Kg]')

plot right bar

ax2.plot(X, y2 ,ls=':', lw=0.5, c='r', alpha=0.3)
ax2.set_ylim(0, 30)
ax2.set_ylabel('y2 for left_bar [m]')

show

ax.set_title('twin_X')
fig
plt.show()