title: How to add unit to axis-label at 'ridge plot' from seaborn
body: <p>I would like to do following based on the seaborn 'ridge plot' example (<a href="https://seaborn.pydata.org/examples/kde_ridgeplot.html" rel="nofollow noreferrer">https://seaborn.pydata.org/examples/kde_ridgeplot.html</a>):</p>
  <p>I want to add the unit to the x label of the x-axis, such that it appears as <em>x in [m]</em> in the plot. How do I do that? Extending the command <code>g.map(label, &quot;x&quot;)</code> to <code>g.map(label, &quot;x in [m]&quot;)</code> leads to following error: <em>KeyError: &quot;['x [m]'] not in index&quot;</em></p>
  <p>My code is the following one:</p>
  <pre><code>import numpy as np
  import pandas as pd
  import seaborn as sns
  import matplotlib.pyplot as plt
  sns.set(style=&quot;white&quot;, rc={&quot;axes.facecolor&quot;: (0, 0, 0, 0)})
  
  
  errorNames = ['Error 1 - abc.....',
                'Error 2 - abc.....',
                'Error 3 - abc.....',
                'Error 4 - abc.....',
                'Error 5 - abc.....',
                'Error 6 - abc.....',
                'Error 7 - abc.....',
                'Error 8 - abc.....',
                'Error 9 - abc.....',
                'Error 10 - abc.....',
                'Error 11 - abc.....',
                'Error 12 - abc.....',
                'Error 13 - abc.....']
  
  
  # Create the data
  rs = np.random.RandomState(1979)
  x = rs.randn(650)
  #g = np.tile(list(&quot;ABCDEFGHIJKLM&quot;), 50)
  g = np.tile(list(errorNames), 50)
  
  df = pd.DataFrame(dict(x=x, g=g))
  #m = df.g.map(ord)
  #df[&quot;x&quot;] += m
  
  # Initialize the FacetGrid object
  pal = sns.cubehelix_palette(10, rot=-.25, light=.7)
  g = sns.FacetGrid(df, row=&quot;g&quot;, hue=&quot;g&quot;, aspect=15, height=.5, palette=pal)
  
  # Draw the densities in a few steps
  g.map(sns.kdeplot, &quot;x&quot;, clip_on=False, shade=True, alpha=1, lw=1.5, bw=.2)
  g.map(sns.kdeplot, &quot;x&quot;, clip_on=False, color=&quot;w&quot;, lw=2, bw=.2)
  g.map(plt.axhline, y=0, lw=2, clip_on=False)
  
  
  #sns.plt.xlim(-10, 3)
  
  
  # Define and use a simple function to label the plot in axes coordinates
  def label(x, color, label):
      ax = plt.gca()
      ax.text(0, .2, label, fontweight=&quot;bold&quot;, color=color,
              ha=&quot;left&quot;, va=&quot;center&quot;, transform=ax.transAxes)
  
  g.map(label, &quot;x&quot;)
  #g.map(label, &quot;x [m]&quot;)
  
  # Set the subplots to overlap 
  # Erst hier wird geplotted
  g.fig.subplots_adjust(hspace=-.25)
  
  
  # Remove axes details that don't play well with overlap
  g.set_titles(&quot;&quot;)
  g.set(yticks=[])
  g.despine(bottom=True, left=True)
  </code></pre>