What is a violin plot?
A violin plot combines:
- A KDE distribution shape
- A box-plot-like summary inside
It’s useful when you want to see the shape of distributions (multi-modal, skew).
flowchart LR A["Numeric column
per category"] --> B["Compute KDE
for each category"] B --> C["Mirror the KDE curve
left and right"] C --> D["Overlay a mini box
plot in the middle"]
Violin plot in Seaborn
import seaborn as sns
import matplotlib.pyplot as plt
tips = sns.load_dataset("tips")
plt.figure(figsize=(7, 4))
sns.violinplot(data=tips, x="day", y="total_bill")
plt.title("Total bill distribution by day")
plt.tight_layout()
plt.show()Add inner summary
import seaborn as sns
import matplotlib.pyplot as plt
tips = sns.load_dataset("tips")
plt.figure(figsize=(7, 4))
sns.violinplot(data=tips, x="day", y="total_bill", inner="quartile")
plt.title("Violin plot with quartiles")
plt.tight_layout()
plt.show()Visualize it
The width of the violin at any height shows how common values near that height are — wider means more data points cluster there:
When to prefer violin vs box
- Use box plots for quick comparisons and outlier focus.
- Use violin plots when the distribution shape matters.
Check your understanding
What does a violin plot combine?
The violin outline is a KDE and the inside shows a box-like summary.
Show answer
A — A KDE distribution shape and a box-plot-like summary — The violin outline is a KDE and the inside shows a box-like summary.
Which data feature can a violin plot reveal that a box plot hides?
A box plot shows five numbers only, so bimodal data can look like one wide box.
Show answer
B — Two separate peaks (bimodal data) — A box plot shows five numbers only, so bimodal data can look like one wide box.
What does inner="quartile" do in sns.violinplot?
inner controls the summary drawn inside, and quartile shows Q1, median and Q3.
Show answer
B — Draws the quartile lines inside each violin — inner controls the summary drawn inside, and quartile shows Q1, median and Q3.
When should you prefer a box plot over a violin plot?
Box plots suit quick comparisons and outliers. Violins suit cases where distribution shape matters.
Show answer
C — For quick comparisons and an outlier focus — Box plots suit quick comparisons and outliers. Violins suit cases where distribution shape matters.
Next
Continue to Bar Plots in Seaborn to compare an aggregated value (like a mean) across categories, with confidence intervals.
🧪 Try It Yourself
Exercise 1 – A Basic Violin Plot
Tab indents. Press Escape, then Tab, to leave the editor. Control plus Enter runs the code; Control plus Shift plus Enter submits it.
Press Run to see what your code prints.Exercise 2 – Show Quartiles Inside
Tab indents. Press Escape, then Tab, to leave the editor. Control plus Enter runs the code; Control plus Shift plus Enter submits it.
Press Run to see what your code prints.Exercise 3 – Box vs Violin
Tab indents. Press Escape, then Tab, to leave the editor. Control plus Enter runs the code; Control plus Shift plus Enter submits it.
Press Run to see what your code prints.