Section: Boxplot et Violinplot | Data Visualization on Seaborn

Section outline

A common graphical representation of data is the box plot, which can be accessed using boxplot().

signature boxplot

Parameter name	Description	Format	Example
data	The dataframe you are working on	DataFrame, Series, dict, array, or list of arrays	data=table
x	Variable for the x-axis	String corresponding to a variable	x="weight"
y	Variable for the y-axis	String corresponding to a variable	y=”height”
hue	Allows to add a variable as different colors	String corresponding to a variable	hue=”age”
dodge	Variable allowing to choose if the contents of the graphs overlap	Boolean	dodge=False
width	Variable controlling the width of the boxes	Float	width=0.5
gap	Variable controlling the gap between different boxes	Float	gap=0.1

Here is an example of code:

data = sns.load_dataset("penguins")
sns.boxplot(data=data, x="bill_length_mm", hue="island", dodge=True, width=0.5)
plt.show()

boxplot sans gap
By default, gap is set to 0. The orientation is handled automatically by Seaborn, but if the plot is two-dimensional, it can be chosen manually.

data = sns.load_dataset("penguins")
sns.boxplot(data=data, x="bill_length_mm", hue="island", dodge=True, width=0.5, gap=0.1, log_scale=True)
plt.show()

boxplot gap

log_scale allows you to change the scale. A numeric value sets the base. If the plot is two-dimensional, two values can be provided, one for each axis.

The violin plot is also accessible via violinplot().

signature violinplot

Parameter name	Description	Format	Example
data	The dataframe you are working on	DataFrame, Series, dict, array, or list of arrays	data=table
x	Variable for the x-axis	String corresponding to a variable	x="weight"
y	Variable for the y-axis	String corresponding to a variable	y=”height”
hue	Allows to add a variable as different colors	String corresponding to a variable	hue=”age”
inner	Variable allowing to choose the inner representation of the violin	String corresponding to a representation type	inner=”box”,inner=”quart”,inner=”point”
split	Variable allowing to choose to show 2 data groups on the same violin.	Boolean	split=True
width	Variable controlling the width of the boxes	Float	width=0.5
dodge	Variable allowing to choose if the contents of the graphs overlap	Boolean	dodge=False
gap	Variable controlling the gap between different boxes when dodge is True	Float	gap=0.1

Here is an example of code:

data = sns.load_dataset("penguins")
sns.violinplot(data=data, x="bill_length_mm", hue="sex", dodge=True, linewidth=3, split=True, inner="point")
plt.show()

violinplot point

We can choose to display a small box plot within the violin plot:

data = sns.load_dataset("penguins")
sns.violinplot(data=data, x="bill_length_mm", hue="sex",dodge=True,linewidth=3, split=True, inner="box")
plt.show()

violin plot box