title: how to mark the x axis more than 8 points in pyplot polar
body: <p>I want to mark my plot as 24 hours and i need to mark every hour.
  I tried the following code, but the plot only divide into 8 and only mark upto 7.</p>
  
  <pre><code>theta = np.arange(0, 360 + 360 / 144, 360 / 144) * np.pi / 180
  fig1 = plt.figure()
  ax1 = fig1.add_axes([0.1, 0.1, 0.8, 0.8], polar=True)
  ax1.set_ylim(0, 4000)
  ax1.set_yticks(device_dict[name])
  ax1.set_xticklabels(range(24))
  ax1.plot(theta, inter_data)
  </code></pre>
  
  <p>how can i make it mark all 24</p>