如果您从点（0，0）开始绘图，因此不需要考虑不在第一象限内的多边形的面积，那么在这种特殊情况下应该可以解决这个问题：
import matplotlib.pyplot as pltimport numpy as npx = np.arange(0,10,0.1)# The lines to ploty1 = 4 - 2*xy2 = 3 - 0.5*xy3 = 1 -x# The upper edge of polygon (min of lines y1 & y2)y4 = np.minimum(y1, y2)# Set y-limit, making neg y-values not show in plotplt.ylim(0, 5)# Plotting of linesplt.plot(x, y1, x, y2, x, y3)# Filling between line y3 and line y4plt.fill_between(x, y3, y4, color='grey', alpha='0.5')plt.show()
