title: Dendogram Coloring by groups
body: <p>I created a <a href="https://i.stack.imgur.com/hgqt0.png" rel="nofollow noreferrer">heatmap</a> based on spearman's correlation matrix using seaborn clustermap as folowing: I want to paint the dendrogram. I want the dendrogram to look like this:
  <a href="https://i.stack.imgur.com/GS1do.png" rel="nofollow noreferrer">dendrogram</a>
  but on the heatmap</p>
  
  <p>I created a dict of colors as folowing and got an error:</p>
  
  <pre><code>def assign_tree_colour(name,val_dict,coding_names_df):
  ret = None
  if val_dict.get(name, '') == 'Group 1':
      ret = "(0,0.9,0.4)"   #green
  elif val_dict.get(name, '') == 'Group 2':
      ret = "(0.6,0.1,0)"   #red
  elif val_dict.get(name, '') == 'Group 3':
      ret = "(0.3,0.8,1)"   #light blue
  elif val_dict.get(name, '') == 'Group 4':
      ret = "(0.4,0.1,1)"   #purple
  elif val_dict.get(name, '') == 'Group 5':
      ret = "(1,0.9,0.1)"   #yellow
  elif val_dict.get(name, '') == 'Group 6':
      ret = "(0,0,0)"   #black
  else:
      ret = "(0,0,0)"         #black
  return ret
  
  def fix_string(str):
      return str.replace('"', '')
  
  external_data3 = [list(z) for z in coding_names_df.values]
  external_data3 = {fix_string(z[0]): z[3] for z in external_data3}
  
  tree_label = list(df.index)
  tree_label = [fix_string(x) for x in tree_label]
  tree_labels = { j : tree_label[j] for j in range(0, len(tree_label) ) }
  
  tree_colour = [assign_tree_colour(label, external_data3, coding_names_df) for label in tree_labels]
  tree_colors = { i : tree_colour[i] for i in range(0, len(tree_colour) ) }
  
  
  sns.set(color_codes=True)
  sns.set(font_scale=1)
  g = sns.clustermap(df, cmap="bwr",
                     vmin=-1, vmax=1,
                     yticklabels=1, xticklabels=1,
                     cbar_kws={"ticks":[-1,-0.5,0,0.5,1]},
                     figsize=(13,13),
                     row_colors=row_colors,
                     col_colors=col_colors,
                     method='average',
                     metric='correlation',
                     tree_kws=dict(colors=tree_colors))
  g.ax_heatmap.set_xlabel('Genus')
  g.ax_heatmap.set_ylabel('Genus')
  for label in Group.unique():
      g.ax_col_dendrogram.bar(0, 0, color=lut[label],
                              label=label, linewidth=0)
  g.ax_col_dendrogram.legend(loc=9, ncol=7, bbox_to_anchor=(0.26, 0., 0.5, 1.5))
  ax=g.ax_heatmap
  
  
  
   File "&lt;ipython-input-64-4bc6be89afe3&gt;", line 11, in &lt;module&gt;
  tree_kws=dict(colors=tree_colors))
  
  
  
  File "C:\Users\rotemb\AppData\Local\Continuum\anaconda3\lib\site-packages\seaborn\matrix.py", line 1391, in clustermap
      tree_kws=tree_kws, **kwargs)
  
    File "C:\Users\rotemb\AppData\Local\Continuum\anaconda3\lib\site-packages\seaborn\matrix.py", line 1208, in plot
      tree_kws=tree_kws)
  
    File "C:\Users\rotemb\AppData\Local\Continuum\anaconda3\lib\site-packages\seaborn\matrix.py", line 1054, in plot_dendrograms
      tree_kws=tree_kws
  
    File "C:\Users\rotemb\AppData\Local\Continuum\anaconda3\lib\site-packages\seaborn\matrix.py", line 776, in dendrogram
      return plotter.plot(ax=ax, tree_kws=tree_kws)
  
    File "C:\Users\rotemb\AppData\Local\Continuum\anaconda3\lib\site-packages\seaborn\matrix.py", line 692, in plot
      **tree_kws)
  
    File "C:\Users\rotemb\AppData\Local\Continuum\anaconda3\lib\site-packages\matplotlib\collections.py", line 1316, in __init__
      colors = mcolors.to_rgba_array(colors)
  
    File "C:\Users\rotemb\AppData\Local\Continuum\anaconda3\lib\site-packages\matplotlib\colors.py", line 294, in to_rgba_array
      result[i] = to_rgba(cc, alpha)
  
    File "C:\Users\rotemb\AppData\Local\Continuum\anaconda3\lib\site-packages\matplotlib\colors.py", line 177, in to_rgba
      rgba = _to_rgba_no_colorcycle(c, alpha)
  
    File "C:\Users\rotemb\AppData\Local\Continuum\anaconda3\lib\site-packages\matplotlib\colors.py", line 240, in _to_rgba_no_colorcycle
      raise ValueError("Invalid RGBA argument: {!r}".format(orig_c))
  
  ValueError: Invalid RGBA argument: 0
  </code></pre>
  
  <p>Any help on this would be greatly appreciated!
  Tnx!</p>