Boxplot : custom width in seaborn

3
votes

I am trying to plot boxplots in seaborn whose widths depend upon the log of the value of x-axis. I am creating the list of widths and passing it to the widths=widths parameter of seaborn.boxplot.

However, I am getting that

raise ValueError(datashape_message.format("widths"))
ValueError: List of boxplot statistics and `widths` values must have same the length

When I debugged and checked there is just one dict in boxplot statistics, whereas I have 8 boxplots. Cannot Exactly figure out where the problem lies.

Here is the image of the Boxplot

I am using pandas data frame and seaborn for plotting.

1
pythonmatplotlibseabornboxplot

1 Answers

1
votes

Seaborn's boxplot doesn't seem to understand the widths= parameter.

Here is a way to create a boxplot per x value via matplotlib's boxplot which does accept the width= parameter. The code below supposes the data is organized in a panda's dataframe.

from matplotlib import pyplot as plt
import numpy as np
import pandas as pd
import seaborn as sns

df = pd.DataFrame({'x': np.random.choice([1, 3, 5, 8, 10, 30, 50, 100], 500),
                   'y': np.random.normal(750, 20, 500)})
xvals = np.unique(df.x)
positions = range(len(xvals))
plt.boxplot([df[df.x == xi].y for xi in xvals],
            positions=positions, showfliers=False,
            boxprops={'facecolor': 'none'}, medianprops={'color': 'black'}, patch_artist=True,
            widths=[0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9])
means = [np.mean(df[df.x == xi].y) for xi in xvals]
plt.plot(positions, means, '--k*', lw=2)
# plt.xticks(positions, xvals) # not needed anymore, as the xticks are set by the swarmplot
sns.swarmplot('x', 'y', data=df)
plt.show()

example plot