title: animated subplots using matplotlib
body: <p>I have this code. I want to add a subplot to draw the cosine function. (I do not want to create a class). The second plot should be dynamically updated as well</p>
  
  <pre><code>import numpy as np
  import matplotlib.pyplot as plt
  import matplotlib.animation as animation
  
  def data_gen():
      t = data_gen.t
      cnt = 0
      while cnt &lt; 1000:
          cnt+=1
          t += 0.05
          yield t, np.sin(2*np.pi*t) * np.exp(-t/10.)
  data_gen.t = 0
  
  fig, ax = plt.subplots()
  line, = ax.plot([], [], lw=2)
  ax.set_ylim(-1.1, 1.1)
  ax.set_xlim(0, 5)
  ax.grid()
  xdata, ydata = [], []
  def run(data):
      # update the data
      t,y = data
      xdata.append(t)
      ydata.append(y)
      xmin, xmax = ax.get_xlim()
  
      if t &gt;= xmax:
          ax.set_xlim(xmin, 2*xmax)
          ax.figure.canvas.draw()
      line.set_data(xdata, ydata)
  
      return line,
  
  ani = animation.FuncAnimation(fig, run, data_gen, blit=True, interval=10,
      repeat=False)
  plt.show()
  </code></pre>