title: Plotting one data set with two unrelated y axes-matplotlib
body: <p>I'm trying to plot one data set with two different unrelated y axes. I've tried using twinx, but that just makes two plots on the same graph. I want there to be one point corresponding to two y values.</p>
  
  <p>This is what I have so far:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  
  x=[range(1,16)] 
  y=[13.03,13.03,13.03,13.04,13.04,13.05,13.05,13.07,13.07,13.10,13.10,13.13,13.18‌​,13.23,13.39] 
  y2=[6.944,6.964,6.972,7.008,7.045,7.085,7.109,7.213,7.215,7.5,7.51,7.73,8.2,8.68‌​,11.09] 
  fig, ax1=plt.subplots() 
  
  ax1.set_xlabel("Time",fontsize=14) 
  ax1.set_ylabel("Lookback Time\nGly",fontsize=14) 
  ax2=ax1.twinx() 
  ax2.set_ylabel("z",fontsize=14) 
  ax1.set_ylim(13.00,13.40) 
  ax2.set_ylim(6.800,11.200) 
  ax1.set_xlim(0,16) 
  ax1.scatter(x,y, label="Lookback Time", s=80,color='b' )#marker='^') ax2.scatter(x,y2, label="z", s=80,color="r")
  
  plt.show()
  </code></pre>