Nested subplots with subfigures in Matplotlib - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a figure with subfigures using matplotlib.

Matplotlib

import matplotlib.pyplot as plt
fig = plt.figure(constrained_layout=True)
subfigs = fig.subfigures(1, [1])
plt.show()

Drag options to blanks, or click blank then click option'

A1

B3

C4

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 instead of 2 for the number of subfigures.

Confusing rows and columns in subfigures.

The code creates one row of subfigures with 2 columns, so the correct argument is 2.

2fill in blank

medium

Complete the code to add a 2x2 grid of subplots inside the first subfigure.

Matplotlib

axs = subfigs[0].subplots([1], 2)
plt.show()

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A4

B2

C3

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 or 3 instead of 2 for the number of rows.

Confusing rows and columns.

To create a 2x2 grid, the number of rows is 2 and columns is 2.

3fill in blank

hard

Fix the error in the code to add a title to the second subfigure.

Matplotlib

subfigs[[1]].suptitle('Second Subfigure')
plt.show()

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A2

B0

C1

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using 2 or 3 which are out of range for two subfigures.

Using 0 which is the first subfigure.

The second subfigure is at index 1 because indexing starts at 0.

4fill in blank

hard

Fill both blanks to create a 1x3 grid of subplots inside the second subfigure.

Matplotlib

axs2 = subfigs[1].subplots([1], [2])
plt.show()

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A1

B2

C3

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping rows and columns.

Using 2 instead of 1 for rows.

To create a 1 row and 3 columns grid, use 1 and 3 respectively.

5fill in blank

hard

Fill all three blanks to plot a line on the first subplot of the first subfigure.

Matplotlib

axs.flat[[1]].plot([2], [3])
plt.show()

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A0

B[1, 2, 3, 4]

C[10, 20, 25, 30]

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 1 instead of 0 for the first subplot.

Swapping x and y data lists.

The first subplot is index 0; x values are [1, 2, 3, 4]; y values are [10, 20, 25, 30].

Practice

1. What is the main purpose of using fig.subfigures() in matplotlib?

easy

A. To add a single plot to a figure

B. To create large groups inside a figure that can hold their own smaller plots

C. To change the color of a plot

D. To save a figure as an image file

Solution

1. Step 1: Understand the role of fig.subfigures()

   This method creates subfigures, which are large groups inside a main figure.

2. Step 2: Recognize the use of subfigures

   Each subfigure can contain its own grid of smaller plots, helping organize complex layouts.

3. Final Answer:

   To create large groups inside a figure that can hold their own smaller plots -> Option B

4. Quick Check:

   Subfigures = large groups inside figure [OK]

Hint: Subfigures group plots inside a figure [OK]

Common Mistakes:

• Thinking subfigures add only one plot
• Confusing subfigures with saving figures
• Assuming subfigures change plot colors

2. Which of the following is the correct way to create two subfigures side by side in matplotlib?

easy

A. fig.subplots(1, 2)

B. fig.subfigures(2, 1)

C. fig.subfigures(1, 2)

D. fig.subfigures(2, 2)

Solution

1. Step 1: Understand subfigures layout parameters

   The parameters (rows, columns) define the grid of subfigures. For side by side, use 1 row and 2 columns.

2. Step 2: Match parameters to options

   fig.subfigures(1, 2) uses fig.subfigures(1, 2), which creates 1 row and 2 columns, placing subfigures side by side.

3. Final Answer:

   fig.subfigures(1, 2) -> Option C

4. Quick Check:

   Side by side = 1 row, 2 columns [OK]

Hint: Rows first, columns second in subfigures() [OK]

Common Mistakes:

• Swapping rows and columns
• Using subplots() instead of subfigures()
• Choosing more rows than needed

3. What will be the output shape of the axes array when running this code?

fig = plt.figure()
subfigs = fig.subfigures(2, 1)
ax1 = subfigs[0].subplots(1, 3)
ax2 = subfigs[1].subplots(2, 2)
print(ax1.shape, ax2.shape)

medium

A. (1, 3) (4,)

B. (3,) (4,)

C. (3,) (2, 2)

D. (1, 3) (2, 2)

Solution

1. Step 1: Analyze subfigures and their subplot grids

   First subfigure has 1 row and 3 columns, so ax1 shape is (1, 3). Second subfigure has 2 rows and 2 columns, so ax2 shape is (2, 2).

2. Step 2: Confirm shapes printed

   Printing ax1.shape and ax2.shape outputs (1, 3) and (2, 2) respectively.

3. Final Answer:

   (1, 3) (2, 2) -> Option D

4. Quick Check:

   Subplots shape = (rows, columns) [OK]

Hint: Shape matches (rows, columns) in subplots() [OK]

Common Mistakes:

• Confusing flat arrays with 2D arrays
• Mixing up rows and columns
• Assuming subfigures affect shape differently

4. Identify the error in this code snippet for creating nested subplots with subfigures:

fig = plt.figure()
subfigs = fig.subfigures(1, 2)
ax = subfigs.subplots(2, 2)

medium

A. subfigs.subplots() should be called on each subfigure, not on the list

B. fig.subfigures() requires 3 arguments, missing one

C. subfigs is a list, so subfigs.subplots() is invalid

D. subfigures cannot have nested subplots

Solution

1. Step 1: Understand the type of subfigs

   fig.subfigures(1, 2) returns a list or array of subfigure objects, not a single subfigure.

2. Step 2: Correct method call for subplots

   We must call subplots() on each individual subfigure, not on the entire list subfigs.

3. Final Answer:

   subfigs.subplots() should be called on each subfigure, not on the list -> Option A

4. Quick Check:

   Call subplots() on single subfigure [OK]

Hint: Call subplots() on one subfigure, not list [OK]

Common Mistakes:

• Calling subplots() on the list of subfigures
• Assuming subfigures() needs 3 args
• Thinking subfigures can't have subplots

5. You want to create a figure with 2 subfigures stacked vertically. The top subfigure should have a 2x2 grid of plots, and the bottom subfigure a single plot. Which code correctly achieves this?

hard

A. fig = plt.figure()
subfigs = fig.subfigures(2, 1)
axs_top = subfigs[0].subplots(2, 2)
axs_bottom = subfigs[1].subplots(1, 1)

B. fig = plt.figure()
subfigs = fig.subfigures(1, 2)
axs_top = subfigs[0].subplots(2, 2)
axs_bottom = subfigs[1].subplots(1, 1)

C. fig = plt.figure()
subfigs = fig.subfigures(2, 1)
axs_top = subfigs.subplots(2, 2)
axs_bottom = subfigs.subplots(1, 1)

D. fig = plt.figure()
subfigs = fig.subfigures(1, 2)
axs_top = subfigs.subplots(2, 2)
axs_bottom = subfigs.subplots(1, 1)

Solution

1. Step 1: Set subfigures layout vertically

   Two subfigures stacked vertically means 2 rows and 1 column, so fig.subfigures(2, 1).

2. Step 2: Create subplots inside each subfigure

   Top subfigure gets a 2x2 grid, bottom subfigure gets a single plot (1x1). Call subplots() on each subfigure individually.

3. Final Answer:

   fig = plt.figure() subfigs = fig.subfigures(2, 1) axs_top = subfigs[0].subplots(2, 2) axs_bottom = subfigs[1].subplots(1, 1) -> Option A

4. Quick Check:

   Vertical stack = (2,1), call subplots() on each subfigure [OK]

Hint: Vertical stack = (2,1), subplots() on each subfigure [OK]

Common Mistakes:

• Using (1,2) for vertical stacking
• Calling subplots() on the list of subfigures
• Not matching subplot grids to subfigures