title: Seaborn: How to add vertical lines to a distribution plot (sns.distplot)
body: <p>Using the examples from <a href="https://seaborn.pydata.org/generated/seaborn.distplot.html" rel="noreferrer">seaborn.pydata.org</a> and the <a href="https://jakevdp.github.io/PythonDataScienceHandbook/04.14-visualization-with-seaborn.html" rel="noreferrer">Python DataScience Handbook</a>, I'm able to produce a combined distribution plot with the following snippet:</p>
  
  <p><strong>Code:</strong></p>
  
  <pre><code>import pandas as pd
  import numpy as np
  import seaborn as sns
  import matplotlib.pyplot as plt
  
  # some settings
  sns.set_style("darkgrid")
  
  # Create some data
  data = np.random.multivariate_normal([0, 0], [[5, 2], [2, 2]], size=2000)
  data = pd.DataFrame(data, columns=['x', 'y'])
  
  # Combined distributionplot
  sns.distplot(data['x'])
  sns.distplot(data['y'])
  </code></pre>
  
  <p><strong>Plot:</strong>
  <a href="https://i.stack.imgur.com/vkMpc.png" rel="noreferrer"><img src="https://i.stack.imgur.com/vkMpc.png" alt="enter image description here"></a></p>
  
  <p>How can I combine this setup with vertical lines so that I can illustrate thresholds like this:</p>
  
  <p><a href="https://i.stack.imgur.com/H5CBT.png" rel="noreferrer"><img src="https://i.stack.imgur.com/H5CBT.png" alt="enter image description here"></a></p>
  
  <p>I know I can do it with matplotlib like here <a href="https://stackoverflow.com/questions/52112092/dynamic-histogram-subplots-with-line-to-mark-target/52114420#52114420">Dynamic histogram subplots with line to mark target</a>, but I really like the simplicity of seaborn plots and would like to know if it's possible to do it more elegantly (and yes, I know that seaborn builds on top of matplotlib).</p>
  
  <p>Thank you for any suggestions!</p>