python 画折线图

import matplotlib.pylab as pl
def drew_lines():
    x = [1,2,3,4,5,6,7,8,9,10,11,12,13]
    y = [0, 1, 0, 2, 4, 6, 8, 6, 8, 8, 9, 11, 12]
    pl.plot(x,y)
    pl.grid(True)
    pl.scatter(x, y)
    pl.show()
if __name__=="__main__":
    drew_lines()