title: How to center the bar plot to show the difference of a certain column?
body: <p><strong>How to center the bar plot to show the difference of a certain column?</strong></p>
  
  <p>I have the following bar plot, done with matplotlib : <a href="https://i.stack.imgur.com/Soir4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Soir4.png" alt="Bar plot"></a></p>
  
  <p>Note how the barplot is really bad. The difference between each bar cant really be seen properly. So what I want, is to use the red bar as the origin in the y-axis. That way, the other bars would show the difference (blue_bar(i) - redbar).</p>
  
  <p>In other words, I want the value of the red bar in the y-axis to be the y-origin of the plot. </p>
  
  <p>Again, in another words, the red bar is the accuracy obtained by my academic work. I want to plot the other article results compared/ <strong>IN RELATION</strong> to mine.</p>
  
  <p>I made the following picture using paint.net to illustrate what I want.
  Any other ideas/suggestions are really appreciated.</p>
  
  <p><a href="https://i.stack.imgur.com/cbnnM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cbnnM.png" alt="enter image description here"></a></p>
  
  <p>Appendix :</p>
  
  <p>I used the following code to produce the first graphic :</p>
  
  <pre><code>import numpy as np
  import random
  from matplotlib import pyplot as plt
  
  accuracies = [0.9630, 0.9597, 0.9563, 0.9533, 0.9527, 0.9480, 0.9477, 0.9472, 0.9472, 0.9466, 0.9452, 0.9452, 0.9442,
                0.9440, 0.9434, 0.9420, 0.9407, 0.9407, 0.9391, 0.9377, 0.9185, 0.9268]
  
  sensitividades = [0.7680, 0.7200, 0.8173, 0.7569, 0.7406, 0.7354, 0.7746, 0.7344, 0.7067, 0.7410, 0.7370, 0.7321,
                    0.7357]
  
  especificidades = [0.9827, 0.9733, 0.9816, 0.9807, 0.9789, 0.9724, 0.9764, 0.9801, 0.9751, 0.9521, 0.9487, 0.9694]
  
  accuracies = [x * 100 for x in accuracies]
  
  y = accuracies
  
  N = len(y)
  x = range(N)
  width = 1 / 1.1
  fig, ax = plt.subplots(1, 1)
  ax.grid(zorder=0)
  
  # Plot other articles
  ax.bar(x, y, width, color="blue", zorder=3)
  
  # Plot my work
  ax.bar(x[len(x) - 1] + 1, 95.30, width, color="red", zorder=3)
  
  plt.title('Accuracy of each article')
  plt.xlabel('Article')
  plt.ylabel('Accuracy')
  
  plt.savefig('foo.png')
  plt.show()
  </code></pre>