pyplot second y axis

1import numpy as np
2import matplotlib.pyplot as plt
3
4# Create some mock data
5t = np.arange(0.01, 10.0, 0.01)
6data1 = np.exp(t)
7data2 = np.sin(2 * np.pi * t)
8
9fig, ax1 = plt.subplots()
10
11color = 'tab:red'
12ax1.set_xlabel('time (s)')
13ax1.set_ylabel('exp', color=color)
14ax1.plot(t, data1, color=color)
15ax1.tick_params(axis='y', labelcolor=color)
16
17ax2 = ax1.twinx()  # instantiate a second axes that shares the same x-axis
18
19color = 'tab:blue'
20ax2.set_ylabel('sin', color=color)  # we already handled the x-label with ax1
21ax2.plot(t, data2, color=color)
22ax2.tick_params(axis='y', labelcolor=color)
23
24fig.tight_layout()  # otherwise the right y-label is slightly clipped
25plt.show()
26

1import numpy as np
2import matplotlib.pyplot as plt
3x = np.arange(0, 10, 0.1)
4y1 = 0.05 * x**2
5y2 = -1 *y1
6
7fig, ax1 = plt.subplots()
8
9ax2 = ax1.twinx()
10ax1.plot(x, y1, 'g-')
11ax2.plot(x, y2, 'b-')
12
13ax1.set_xlabel('X data')
14ax1.set_ylabel('Y1 data', color='g')
15ax2.set_ylabel('Y2 data', color='b')
16
17plt.show()