title: Python: Barplot with colorbar
body: <p>I'm trying to make a bar plot with a color bar, each bar's hight is one variable (y) and each bar should have a color depending on another variable (c).</p>
  
  <p>What I've got to is this (simple example):</p>
  
  <pre><code>data_x = [0,1,2,3]
  data_hight = [60,60,80,100]
  data_color = [1000,500,1000,900]
  
  
  data_color = [x / max(data_color) for x in data_color]
  fig, ax = plt.subplots(figsize=(15, 4))
  
  my_cmap = plt.cm.get_cmap('GnBu')
  colors = my_cmap(data_color)
  rects = ax.bar(data_x, data_hight, color=colors)
  
  CS = plt.contourf([data_x, data_color],cmap=my_cmap)
  
  cbar = plt.colorbar(CS, cmap=my_cmap)
  cbar.set_label('Color', rotation=270,labelpad=25)
  
  plt.xticks(data_x)    
  plt.ylabel("Y")
  
  plt.show()
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/IGyB3.png" alt=""></p>
  
  <p>The main problem is that the histogram colors are fine but the color bar is in a diferent scale. besides that I can see a blue line at y=0, it shouldn't be there.</p>
  
  <p>Any help will be a preciated.
  Thanks!</p>