Donut chart variation in Matplotlib - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple donut chart code

What will be the output of this code snippet that creates a donut chart using matplotlib?

Matplotlib

import matplotlib.pyplot as plt

sizes = [30, 20, 50]
labels = ['A', 'B', 'C']

plt.pie(sizes, labels=labels, wedgeprops=dict(width=0.4))
plt.show()

A A pie chart with three slices labeled A, B, C but no hole in the center

B An error because wedgeprops is not a valid argument

C A bar chart with three bars labeled A, B, C

D A pie chart with three slices labeled A, B, C and a hole in the center (donut shape)

💡 Hint

Look at the wedgeprops argument and what width controls in a pie chart.

The wedgeprops argument with width less than 1 creates a donut chart by making a hole in the center of the pie chart.

❓ data_output

intermediate

Number of wedges in a donut chart

Given this code, how many wedges (slices) will the donut chart display?

Matplotlib

import matplotlib.pyplot as plt

sizes = [10, 15, 25, 50]
labels = ['W', 'X', 'Y', 'Z']

plt.pie(sizes, labels=labels, wedgeprops=dict(width=0.3))
plt.show()

A 4

B 3

C 1

D 0

💡 Hint

Count the number of elements in the sizes list.

Each element in sizes corresponds to one wedge in the pie or donut chart.

❓ visualization

advanced

Effect of changing width in donut chart

What visual difference will you see if you change the width in wedgeprops from 0.5 to 0.9 in this donut chart code?

Matplotlib

import matplotlib.pyplot as plt

sizes = [40, 30, 30]
labels = ['Red', 'Green', 'Blue']

plt.pie(sizes, labels=labels, wedgeprops=dict(width=0.5))
plt.show()

A The hole in the center becomes larger, making the donut thinner

B The chart changes to a normal pie chart with no hole

C The hole in the center becomes smaller, making the donut thicker

D The chart disappears because width 0.9 is invalid

💡 Hint

Width controls the thickness of the donut ring; higher width means thicker ring.

Increasing width closer to 1 increases the thickness of the donut ring, making the hole smaller.

🔧 Debug

advanced

Identify the error in donut chart code

What error will this code raise when trying to create a donut chart?

Matplotlib

import matplotlib.pyplot as plt

sizes = [25, 25, 25, 25]
labels = ['Q1', 'Q2', 'Q3', 'Q4']

plt.pie(sizes, labels=labels, wedgeprops={'width': 1.2})
plt.show()

A ValueError because width cannot be greater than 1

B TypeError because wedgeprops must be a dict with string keys

C No error, chart displays normally

D SyntaxError due to wrong dictionary syntax

💡 Hint

Width controls the thickness of the donut ring and must be between 0 and 1.

Width greater than 1 is invalid and causes a ValueError in matplotlib pie charts.

🚀 Application

expert

Customize donut chart with exploded slice

Which code snippet correctly creates a donut chart with the second slice exploded outward?

A plt.pie([20, 30, 50], labels=['X', 'Y', 'Z'], wedgeprops=dict(width=0.4), explode=[0.1, 0, 0])

B plt.pie([20, 30, 50], labels=['X', 'Y', 'Z'], wedgeprops=dict(width=0.4), explode=[0, 0.1, 0])

C plt.pie([20, 30, 50], labels=['X', 'Y', 'Z'], wedgeprops=dict(width=0.4), explode=[0, 0, 0.1])

D plt.pie([20, 30, 50], labels=['X', 'Y', 'Z'], wedgeprops=dict(width=0.4), explode=[0.1, 0.1, 0])

💡 Hint

The explode list controls how far each slice is offset; the second slice is index 1.

To explode the second slice, only the second value in explode should be non-zero.