How to add bar value annotations in jointgrid margins

Question

• How can bar labels be added to the tops of bars in the x and y margins of a seaborn.joinplot or sns.JointGrid?
• How can matplotlib.pyplot.bar_label, as shown in How to add value labels on a bar chart, be applied to the bars in the margins?

import seaborn as sns

# sample data
planets = sns.load_dataset('planets')

# plot
g = sns.jointplot(data=planets, x='distance', y='orbital_period', color='purple', marginal_ticks=True, marker='.',
                  marginal_kws=dict(bins=10, fill=True, log_scale=True, color='purple', stat='probability'))

g.plot_joint(sns.kdeplot, color='purple', zorder=0, levels=10, fill=True, thresh=0.1)

Answer 1

• The margin axes must be used to annotate bars in the jointplot
  • g.ax_marg_x
  • g.ax_marg_y
• This is only a viable option with one group of bars (because of crowding); not with hue=.
• The linked answer in the OP has additional details about maptlotlib.pyplot.bar_label, which don't need to be restated here.
• Tested in python 3.10, matplotlib 3.5.1, seaborn 0.11.2
  • .bar_label is available from matplotlib 3.4.0
  • Assignment expressions (:=) are available from python 3.8
    • [v.get_height().round(3) if v.get_height() > 0 else '' for v in ax_xm.containers[0]] without :=.

planets = sns.load_dataset('planets')

g = sns.jointplot(data=planets, x='distance', y='orbital_period', color='purple', marginal_ticks=True, marker='.', height=7,
                  marginal_kws=dict(bins=10, fill=True, log_scale=True, color='purple', stat='probability'))

g.plot_joint(sns.kdeplot, color='purple', zorder=0, levels=10, fill=True, thresh=0.1)

# alias for the x margin; this is not necessary, just used for conciseness
ax_xm = g.ax_marg_x

# only add labels if the value is greater than 0
xm_labels = [h.round(3) if (h := v.get_height()) > 0 else '' for v in ax_xm.containers[0]]

# annotate the bar
ax_xm.bar_label(ax_xm.containers[0], labels=xm_labels, label_type='edge', rotation=90, padding=4)

# alias for the y margin
ax_ym = g.ax_marg_y

# only add labels if the value is greater than 0
ym_labels = [w.round(3) if (w := v.get_width()) > 0 else '' for v in ax_ym.containers[0]]

# annotate the bar
_ = ax_ym.bar_label(ax_ym.containers[0], labels=ym_labels, label_type='edge', padding=3)