Thank you for your answer. I think that it is the default option in matplotlib.pyplot, but I'm not used to this label.
The plot ylimits go from 1e-8+1 to 9e-8+1. However, the scale of y-axis is 1、2、3、4、5、6、7、8、9, meanwhile label the 1e-8+1 in the top over y-axis. So I felt confusing whether the data is 1e-8+1、2e-8+2、3e-8+3、4e-8+4、...9e-8+9 or 1e-8+1、2e-8+1、3e-8+1、4e-8+1、...9e-8+1. With the suggestion of Pr. Anton Akhmerov, I try this codes: ####################### import numpy as np import matplotlib.pyplot as plt y=1+np.linspace(1,9,100)*1e-8 x=np.linspace(1,9,100) plt.plot(x,y) plt.show() ####################### The latter one is correct: 1e-8+1、2e-8+1、3e-8+1、4e-8+1、...9e-8+1. Sorry about that I don't know how to attach the figure in the community. jinlong zhang
