How to add the repeated hatches to each bar in seaborn.barplot

Question

I want add the repeated hatch patterns over a seaborn barplot.

Of course, I checked the below Q&A, but I cannot solve my question.

Is it possible to add hatches to each individual bar in seaborn.barplot?

In the above Q&A, the different patch patterns are applied to the left blue ('-') and the right blue ('+'). I want apply the same patch pattern to the same color bar; ("//") should be applied on the two blue bar, ("\\") should be applied on the two green bar, and ("|") should be applied on the two red bar.

I tried the below code, but I can not realize my ideal figure.

import matplotlib.pyplot as plt
import seaborn as sns

# Set style
sns.set(style="whitegrid", color_codes=True)

# Load some sample data
titanic = sns.load_dataset("titanic")

# Make the barplot
bar = sns.barplot(x="sex", y="survived", hue="class", data=titanic);

hatches = cycle([ "//" , "\\\\" , "|"])

# Loop over the bars
for i,thisbar in enumerate(bar.patches):
    # Set a different hatch for each bar
    thisbar.set_hatch(hatches[i])

plt.show()

Does this answer your question? [Add hash pattern to a seaborn bar plot](https://stackoverflow.com/questions/42185000/add-hash-pattern-to-a-seaborn-bar-plot) — Trenton McKinney, Jun 17 '22 at 15:01

JohanC · Accepted Answer · 2021-05-07T14:35:29.567

2

sns.barplot returns the matplotlib ax on which the bar plot has been created. (Giving the return value a very different name can be confusing when searching the seaborn and matplotlib documentation for how to make adjustments.)

ax.patches indeed contains all the bars. First come all bars of First Class, then all bars of Second Class, then those of Third class. This grouping can be found in ax.containers which has 3 containers: one for each group of bars. Iterating through these containers helps to hatch each group individually. Later, the legend needs to be created again to also show the hatching.

import matplotlib.pyplot as plt
import seaborn as sns

sns.set(style="whitegrid", color_codes=True)
titanic = sns.load_dataset("titanic")
ax = sns.barplot(x="sex", y="survived", hue="class", data=titanic)

hatches = ["//", "\\\\", "|"]
# Loop over the bars
for bars, hatch in zip(ax.containers, hatches):
    # Set a different hatch for each group of bars
    for bar in bars:
        bar.set_hatch(hatch)
# create the legend again to show the new hatching
ax.legend(title='Class')
plt.show()

edited May 07 '21 at 14:35

answered May 06 '21 at 17:16

JohanC

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Thank you for your quick response. However, I got the error message "NameError: name 'handles' is not defined." matplotlib ver 3.0.3 and seaborn 0.9.0 are used. – rrkk May 07 '21 at 14:28
I deeply appreciated your kind support! I did reproduce the ideal figure. – rrkk May 07 '21 at 14:36
1

Thank you for checking out the code. The `handles` were used in my first tests, but weren't needed, and apparently I only removed them partially. The new code should be correct. – JohanC May 07 '21 at 14:37
Adding a comment to save others time, the order of hatches is reversed by the way ax.containers loops through. Quick fix is to reverse your order of hatches as `hatches = ["//", "\\\\", "|"][::-1]` in example – mapping dom Apr 16 '23 at 09:25

How to add the repeated hatches to each bar in seaborn.barplot

1 Answers1