Exploding slices in Matplotlib - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of pie chart with exploding slices

What will be the output of this code snippet that creates a pie chart with one slice exploded?

Matplotlib

import matplotlib.pyplot as plt
sizes = [15, 30, 45, 10]
labels = ['A', 'B', 'C', 'D']
explode = (0, 0.1, 0, 0)  # only 'B' is exploded
plt.pie(sizes, labels=labels, explode=explode, autopct='%1.1f%%')
plt.show()

A A pie chart with all slices exploded equally and percentages shown.

B A pie chart with slice 'A' exploded and no percentages shown.

C A pie chart with slice 'B' slightly separated from the rest, showing percentages for all slices.

D A pie chart with slice 'D' exploded and no labels shown.

💡 Hint

Look at the explode tuple and which slice it affects.

The explode tuple has 0.1 only for the second slice 'B', so only that slice is separated. autopct shows percentages for all slices.

❓ data_output

intermediate

Number of exploded slices in pie chart

Given the explode parameter below, how many slices will be exploded in the pie chart?

Matplotlib

explode = (0.2, 0, 0.3, 0, 0)

A 2

B 1

C 3

D 0

💡 Hint

Count the non-zero values in the explode tuple.

The explode tuple has two non-zero values: 0.2 and 0.3, so two slices will be exploded.

🔧 Debug

advanced

Identify the error in pie chart explode parameter

What error will this code raise when trying to plot a pie chart with explode parameter?

Matplotlib

import matplotlib.pyplot as plt
sizes = [20, 30, 25]
labels = ['X', 'Y', 'Z']
explode = (0.1, 0.2)  # length mismatch
plt.pie(sizes, labels=labels, explode=explode)
plt.show()

A TypeError: explode must be a list

B ValueError: 'explode' must be same length as 'sizes'

C No error, pie chart plots correctly

D IndexError: tuple index out of range

💡 Hint

Check if explode length matches sizes length.

The explode tuple length is 2 but sizes length is 3, causing a ValueError about length mismatch.

🚀 Application

advanced

Creating a pie chart with multiple exploded slices

You want to create a pie chart with 4 slices where the first and last slices are exploded by 0.1 and 0.2 respectively. Which explode tuple should you use?

A (0.1, 0, 0, 0.2)

B (0.1, 0.2, 0, 0)

C (0, 0.1, 0, 0.2)

D (0.2, 0, 0, 0.1)

💡 Hint

The explode tuple order matches the slice order.

The first slice corresponds to the first explode value (0.1), and the last slice corresponds to the last explode value (0.2).

🧠 Conceptual

expert

Effect of explode values greater than 1 in pie chart

What happens if you set an explode value greater than 1 for a slice in a matplotlib pie chart?

A The slice is not exploded at all.

B Matplotlib raises a ValueError for invalid explode value.

C The explode value is automatically capped at 1.

D The slice is pushed far outside the pie, possibly outside the figure area.

💡 Hint

Explode controls the fraction of radius to offset the slice.

Explode values represent fraction of the radius to offset the slice. Values greater than 1 push the slice far outside the pie, possibly outside the visible area.

Practice

1. What does the explode parameter do in a matplotlib pie chart?

easy

A. It adds labels to the slices.

B. It changes the colors of the slices.

C. It rotates the entire pie chart.

D. It pulls slices out from the pie to highlight them.

Solution

1. Step 1: Understand the role of explode

   The explode parameter is used to offset slices from the center of the pie chart.

2. Step 2: Identify the effect on the pie chart

   This makes the selected slices stand out by pulling them out slightly.

3. Final Answer:

   It pulls slices out from the pie to highlight them. -> Option D

4. Quick Check:

   Exploding slices = pull out slices [OK]

Hint: Explode means pull slices out to highlight [OK]

Common Mistakes:

• Thinking explode changes colors
• Confusing explode with labels
• Assuming explode rotates the pie

2. Which of the following is the correct way to explode the first slice in a pie chart using matplotlib?

easy

A. explode = 0.1

B. explode = [0.1, 0, 0, 0]

C. explode = (0, 0.1, 0, 0)

D. explode = [1, 1, 1, 1]

Solution

1. Step 1: Understand explode format

   The explode parameter expects a list or tuple with one float per slice.

2. Step 2: Identify correct explode for first slice

   To explode only the first slice, set first value > 0 and others 0, so (0.1, 0, 0, 0) or [0.1, 0, 0, 0] is correct.

3. Final Answer:

   explode = (0, 0.1, 0, 0) -> Option C

4. Quick Check:

   Tuple with first >0, rest 0 = explode first slice [OK]

Hint: Use tuple or list with 0.1 for slice to explode [OK]

Common Mistakes:

• Using a single float instead of list or tuple
• Exploding wrong slice by wrong index
• Using all ones explodes all slices

3. What will be the output of this code snippet?

import matplotlib.pyplot as plt
sizes = [30, 20, 25, 25]
explode = [0, 0.2, 0, 0]
plt.pie(sizes, explode=explode, labels=['A', 'B', 'C', 'D'])
plt.show()

medium

A. No slices will be pulled out.

B. The second slice labeled 'B' will be pulled out from the pie.

C. All slices will be pulled out equally.

D. The first slice labeled 'A' will be pulled out from the pie.

Solution

1. Step 1: Analyze the explode list

   The explode list is [0, 0.2, 0, 0], so only the second slice has a positive offset.

2. Step 2: Match explode to labels

   The second slice corresponds to label 'B', so only 'B' will be pulled out.

3. Final Answer:

   The second slice labeled 'B' will be pulled out from the pie. -> Option B

4. Quick Check:

   explode[1] = 0.2 pulls out slice 'B' [OK]

Hint: Check explode list index matching slice label [OK]

Common Mistakes:

• Assuming first slice explodes by default
• Thinking all slices explode with one positive value
• Ignoring explode parameter effect

4. Identify the error in this pie chart code that tries to explode the third slice:

import matplotlib.pyplot as plt
sizes = [10, 20, 30]
explode = [0, 0, 0.1, 0]
plt.pie(sizes, explode=explode)
plt.show()

medium

A. The explode list has more elements than sizes.

B. The explode list has fewer elements than sizes.

C. The explode values must be integers, not floats.

D. The sizes list must be sorted.

Solution

1. Step 1: Compare lengths of sizes and explode

   The sizes list has 3 elements, but explode has 4 elements.

2. Step 2: Understand explode length requirement

   Explode must have the same length as sizes to match each slice.

3. Final Answer:

   The explode list has more elements than sizes. -> Option A

4. Quick Check:

   explode length ≠ sizes length causes error [OK]

Hint: Explode list length must match sizes length [OK]

Common Mistakes:

• Using different lengths for explode and sizes
• Thinking explode values must be integers
• Sorting sizes is unnecessary

5. You want to highlight the largest slice in a pie chart by exploding it. Given sizes = [15, 40, 25, 20], which explode list correctly explodes only the largest slice?

hard

A. [0, 0.1, 0, 0]

B. [0, 0, 0.1, 0]

C. [0.1, 0, 0, 0]

D. [0, 0, 0, 0.1]

Solution

1. Step 1: Identify the largest slice

   The sizes are [15, 40, 25, 20], so the largest slice is the second one with 40.

2. Step 2: Create explode list to highlight largest slice

   Explode list must have 0.1 at index 1 (second slice) and 0 elsewhere: [0, 0.1, 0, 0].

3. Final Answer:

   [0, 0.1, 0, 0] -> Option A

4. Quick Check:

   Largest slice index = 1, explode[1] = 0.1 [OK]

Hint: Find largest slice index, set explode at that index [OK]

Common Mistakes:

• Exploding wrong slice index
• Exploding multiple slices accidentally
• Using explode values > 1