import matplotlib.pyplot as plt

 year=[]

 pop=[]

 year=[1950,1970,1990,2010]+year

 pop=[2.159,3.692,5.263,6.972]+pop

 # plt.plot(year,pop)# X 列 和Y 列

 plt.fill_between(year,pop,0,color="green")#圈出一块区域

 plt.xlabel("Year")#X坐标

 plt.ylabel("Population")#Y坐标

 plt.title("World Population")#标题

 plt.yticks([0,2,4,6,8],["0","2B","4B","6B","8B"])#刻度 表示是以万亿作为单位的



 plt.show()