import numpy as np
import matplotlib.pyplot as plt
x = np.arange(10)
y1 = 2*x
y2 = x**2
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(x, y1, 'b', label="y1")
ax.set_ylabel("label 1")
# 新建一个有共同 x 轴的图
ax2 = ax.twinx()
ax2.plot(x, y2, 'r', label="y2")
ax2.set_ylabel("lable 2")
# 两个 legend 在不同的地方
ax.legend(loc=0)
ax2.legend(loc=4)
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(10)
y1 = 2*x
y2 = x**2
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(x, y1, 'b', label="y1")
ax.set_ylabel("label 1")
# 新建一个有共同 x 轴的图
ax2 = ax.twinx()
ax2.plot(x, y2, 'r', label="y2")
ax2.set_ylabel("lable 2")
fig.legend(loc=[0.13, 0.81])