Boxplot of Multiple Columns of a Pandas Dataframe on the Same Figure (seaborn)

I feel I am probably not thinking of something obvious. I want to put in the same figure, the box plot of every column of a dataframe, where on the x-axis I have the columns' names. In the seaborn.boxplot() this would be equal to groupby by every column.

In pandas I would do

df = pd.DataFrame(data = np.random.random(size=(4,4)), columns = ['A','B','C','D'])
df.boxplot()

which yields

Now I would like to get the same thing in seaborn. But when I try sns.boxplot(df), I get only one grouped boxplot. How do I reproduce the same figure in seaborn?

3 Answers

The seaborn equivalent of

df.boxplot()

is

sns.boxplot(x="variable", y="value", data=pd.melt(df))

or just

sns.boxplot(data=df)

which will plot any column of numeric values, without converting the DataFrame from a wide to long format, using seaborn v0.11.1. This will create a single figure, with a separate boxplot for each column.

Complete example with melt:

import numpy as np; np.random.seed(42)
import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
df = pd.DataFrame(data = np.random.random(size=(4,4)), columns = ['A','B','C','D'])
sns.boxplot(x="variable", y="value", data=pd.melt(df))
plt.show()

This works because pd.melt converts a wide-form dataframe

 A B C D
0 0.374540 0.950714 0.731994 0.598658
1 0.156019 0.155995 0.058084 0.866176
2 0.601115 0.708073 0.020584 0.969910
3 0.832443 0.212339 0.181825 0.183405

to long-form

 variable value
0 A 0.374540
1 A 0.156019
2 A 0.601115
3 A 0.832443
4 B 0.950714
5 B 0.155995
6 B 0.708073
7 B 0.212339
8 C 0.731994
9 C 0.058084
10 C 0.020584
11 C 0.181825
12 D 0.598658
13 D 0.866176
14 D 0.969910
15 D 0.183405

You could use the built-in pandas method df.plot(kind='box') as suggested in this question.
I realize this answer will not help you if you have to use seaborn, but it may be useful for people with simpler requirements.

import numpy as np; np.random.seed(42)
import pandas as pd
import matplotlib.pyplot as plt
df = pd.DataFrame(data = np.random.random(size=(4,4)), columns = ['A','B','C','D'])
df.plot(kind='box')
plt.show()

plt.boxplot([df1,df2], boxprops=dict(color='red'), labels=['title 1','title 2'])