title: Configuring grid-lines in matplotlib plot
body: <p>Consider the figure below. </p>
  
  <p><a href="https://i.stack.imgur.com/e7tgW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/e7tgW.png" alt="enter image description here"></a></p>
  
  <p>This image has been set up with the following code. </p>
  
  <pre><code>  plt.rc('text', usetex=True)
    plt.rc('font', family='serif')
    fig, ax = plt.subplots()
  
    ax.set_xlabel("Run Number", fontsize=25)
  
    plt.grid(True, linestyle='--')
    plt.tick_params(labelsize=20)
    ax.set_xticklabels(map(str,range(number_of_runs)))
    ax.minorticks_on()
  
    ax.set_ylim([0.75,1.75])
  </code></pre>
  
  <p>I have not included the code that actually generates the data for plotting for the sake of clarity. </p>
  
  <p>Unlike the diagram above, I would like to draw grid-lines perpendicular to the X-axis through each orange (and hence blue) dot. How do I do this? 
  The x-coordinates of the successive orange and blue dots form the same arithmetic progression in my code. </p>
  
  <p>Also I notice that the tick numbers numbered 1,2,... are wrong for my application. Instead, I would like each successive grid-line, which I ask for as perpendicular to the X-axis in the previous step, to be numbered sequentially from 1 along the X-axis. How do I configure the Xtick marks for this? </p>