title: Python - colormap in matplotlib for 3D line plot
body: <p>I'm trying to draw a 3D line plot with the toolkits mplot3D of matplotlib
  I have 4 arrays</p>
  
  <ul>
  <li>tab_C[0] is an array of x-value</li>
  <li>tab_C[1] is an array of y-value</li>
  <li>tab_C[2] is an array of z-value</li>
  <li>tab_t is an array of time-value</li>
  </ul>
  
  <p>I've draw my plot with this:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  from mpl_toolkits.mplot3d import Axes3D
  
  fig1 = plt.figure()
  ax = fig1.gca(projection='3d')
  ax.plot(tab_C[0], tab_C[1], tab_C[2])
  
  plt.show()
  </code></pre>
  
  <p>It works but now I want this plot have rainbow coloring based on the time-value. 
  I've searched the web page of matplotlib but there's nothing. Any suggestion on this problem? </p>