seaborn boxplot and stripplot points aren't aligned over the x-axis by hue

Question

I have the following code to draw a boxplot and overlay all data points on the bars.

import pandas as pd
import seaborn as sns
import matplotlib.pyplot as plt
import numpy.random as rnd

f = plt.figure(figsize=[18,12])
ax = f.add_subplot(111)
sns.boxplot(x='month', y='ffdi', hue='scenario', data=df_diff_concat, ax=ax)
sns.stripplot(x="month", y="ffdi",hue='scenario', data=df_diff_concat, ax=ax)

The data points are not vertically aligned with the middleline of the bar they belong to.

How can this be fixed?

Answer 1

• Use dodge=True in seaborn.stripplot, otherwise the values are plotted as a single group centered over the x-tick
• See How to overlay data points on a barplot figure-level plot, where the kind='bar' can be replaced with kind='box'
• Tested in python 3.8.11, matplotlib 3.4.3, seaborn 0.11.2

import seaborn as sns

# load the dataframe
tips = sns.load_dataset('tips')

ax = sns.boxplot(x="day", y="total_bill", hue="smoker", data=tips, palette="GnBu")

# add stripplot with dodge=True
sns.stripplot(x="day", y="total_bill", hue="smoker", data=tips, palette="GnBu", dodge=True, ax=ax, ec='k', linewidth=1)

# remove extra legend handles
handles, labels = ax.get_legend_handles_labels()
ax.legend(handles[:2], labels[:2], title='Smoker', bbox_to_anchor=(1, 1.02), loc='upper left')

• To get the points all in a single line, also set jitter=False, but all data points won't show when there's overlap.

ax = sns.boxplot(x="day", y="total_bill", hue="smoker", data=tips, palette="GnBu")

# add stripplot with dodge=True
sns.stripplot(x="day", y="total_bill", hue="smoker", data=tips, palette="GnBu",
              dodge=True, ax=ax, ec='k', linewidth=1, jitter=False)

# remove extra legend handles
handles, labels = ax.get_legend_handles_labels()
ax.legend(handles[:2], labels[:2], title='Smoker', bbox_to_anchor=(1, 1.02), loc='upper left')

• Use seaborn.swarmplot, which is similar to stripplot(), but the points are adjusted (only along the categorical axis) so that they don’t overlap.

ax = sns.boxplot(x="day", y="total_bill", hue="smoker", data=tips, palette="GnBu")

# add stripplot with dodge=True
sns.swarmplot(x="day", y="total_bill", hue="smoker", data=tips, palette="GnBu",
              dodge=True, ax=ax, ec='k', linewidth=1, size=3)

# remove extra legend handles
handles, labels = ax.get_legend_handles_labels()
ax.legend(handles[:2], labels[:2], title='Smoker', bbox_to_anchor=(1, 1.02), loc='upper left')