python matplotlib 绘制双Y轴曲线图

要点就是ax2 = ax1.twinx()， 制作一个兄弟轴。代码如下：

import matplotlib.pyplot as pltimport numpy as npx = np.arange(0., np.e, 0.01)y1 = np.exp(-x)y2 = np.log(x)fig = plt.figure()ax1 = fig.add_subplot(111)ax1.plot(x, y1)ax1.set_ylabel('Y values for exp(-x)')ax1.set_title("Double Y axis")ax2 = ax1.twinx()  # this is the important functionax2.plot(x, y2, 'r')ax2.set_xlim([0, np.e])ax2.set_ylabel('Y values for ln(x)')ax2.set_xlabel('Same X for both exp(-x) and ln(x)')plt.show()
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绘制结果：