title: Plot an animated line between two points (one is moving) in python
body: <p>Here there´s a fixed point and a variable point, which changes his position every iteration. I would like to animate a line between these two points every iteration, as if there was a line changing his gradient.</p>
  
  <p>Here is the code of these two points:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import numpy as np
  from matplotlib.animation import FuncAnimation
  
  list_var_points = (1, 5, 4, 9, 8, 2, 6, 5, 2, 1, 9, 7, 10)
  
  fig, ax = plt.subplots()
  xfixdata, yfixdata = [14], [8]
  xdata, ydata = [5], []
  ln, = plt.plot([], [], 'ro', animated=True)
  plt.plot([xfixdata], [yfixdata], 'bo')
  
  def init():
      ax.set_xlim(0, 15)
      ax.set_ylim(0, 15)
      return ln,
  
  def update(frame):
      ydata = list_var_points[frame]
      ln.set_data(xdata, ydata)
      return ln,          
  
  
  ani = FuncAnimation(fig, update, frames=range(len(list_var_points)),
              init_func=init, blit=True)
  plt.show()
  </code></pre>
  
  <p>Thank you!</p>