Matplotlib line charts with secondary axis | dual-axis | double-axis

secondary_axis.py

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd

url = 'https://gist.githubusercontent.com/Thiagobc23/4ccb4ea1c612d9d68921bf990ce28855/raw/6225824a6b7d5d273019c09c25cbbaa5b82009bc/dummy_data.csv'
df = pd.read_csv(url, index_col='ID')

# figure
fig, ax = plt.subplots(1, figsize=(12,4), facecolor='#293952')
ax.set_facecolor('#293952')

# data
dt = df.Date
price = df['Price']
rate = df['Exchange Rate']

# plot
plt.plot(dt, price, marker='o', markersize=4, color='#FDAC53', linewidth=2.5)
ax2 = ax.twinx()
ax2.plot(dt, rate, marker='o', markersize=4, color='#55A380', linewidth=2.5)

# ticks
ax.tick_params(axis='both', colors='w')
ax2.tick_params(axis='both', colors='w')
plt.xticks(dt[::3])

# spines
for i in ['top', 'bottom']:
    ax.spines[i].set_visible(False)
    ax2.spines[i].set_visible(False)
    
ax2.spines['left'].set_color('#FDAC53')
ax2.spines['left'].set_linewidth(2)
ax2.spines['right'].set_color('#55A380')
ax2.spines['right'].set_linewidth(2)

# grid
ax.set_axisbelow(True)
ax.xaxis.grid(color='w', linestyle='dashed', alpha=0.5)

# labels n title
ax.set_ylabel('Price', color='w', fontsize=12)
ax2.set_ylabel('Exchange Rate', color='w', fontsize=12)
plt.title('Price and Exchange Rate\n', loc='left', color='w', fontsize=16)

# limits
ax.set_ylim(0,)
ax2.set_ylim(0,)

plt.tight_layout()

#plt.show()
plt.savefig('secondary_axis.png', facecolor='#293952')