title: Formatting y axis datetime.time values as "%H:%M:%S.%f"
body: <p>I am trying to format Y-axis datetime.time values as %H:%M:%S.%f</p>
  
  <p>This code:</p>
  
  <pre><code>fig, axes = plt.subplots(nrows=1, ncols=1, figsize=(20, 5), dpi=150)
  axes.xaxis.set_major_formatter(mdates.DateFormatter('%d-%m-%Y'))
  
  #axes.yaxis.set_major_formatter(mdates.DateFormatter('%H:%M:%S.%f'))
  
  axes.plot_date(test_df["date"],test_df["time"],ydate=True)
  
  plt.gcf().autofmt_xdate()
  </code></pre>
  
  <p>gives</p>
  
  <p><img src="https://i.stack.imgur.com/2XAqd.png" alt="output1"></p>
  
  <p>When I uncomment <code>axes.yaxis.set_major_formatter</code>, the graph shows zeros on the Y-axis:</p>
  
  <p><img src="https://i.stack.imgur.com/qwiR3.png" alt="output2"></p>
  
  <p>Any idea what's wrong?</p>