Plot graph but it does't show

Question

The scatter graph works fine, but the second graph doesn't show. There's no error message or anything. Can anyone help, please. Here's the code.

import matplotlib.pyplot as plt
fig = plt.figure()
ax = fig.add_subplot(111)
ax.scatter(xMat[:,1].flatten().A[0], yMat.T[:,0].flatten().A[0])
plt.show()

xCopy =xMat.copy()
xCopy.sort(0) #x ascending 排列
yHat = xCopy * ws #计算yHat
ax.plot(xCopy[:,1], yHat)
plt.show()

Answer 1

Try this:

import matplotlib.pyplot as plt

plt.figure(1)
plt.subplot(211)
plt.scatter(xMat[:,1].flatten().A[0], yMat.T[:,0].flatten().A[0])

xCopy =xMat.copy()
xCopy.sort(0) #x ascending 排列
yHat = xCopy * ws #计算yHat
plt.subplot(212)
plt.plot(xCopy[:,1], yHat)
plt.show()