只需
plt.show()在末尾致电：
import numpy as npimport matplotlib.pyplot as pltplt.axis([0,50,60,80])for i in np.arange(1,5): z = 68 + 4 * np.random.randn(50) zm = np.cumsum(z) / range(1,len(z)+1) plt.plot(zm)n = np.arange(1,51)su = 68 + 4 / np.sqrt(n)sl = 68 - 4 / np.sqrt(n)plt.plot(n,su,n,sl)plt.show()
